query: in a cross-section of a glacier the greatest flow velocities ( speeds ) occur

pos: Ice-sheet dynamics can be modeled as follows: where: The lowest velocities are near the base of the glacier and along valley sides where friction acts against flow, causing the most deformation. Velocity increases inward toward the center line and upward, as the amount of deformation decreases. The highest flow velocities are found at the surface, representing the sum of the velocities of all the layers below. Glaciers may also move by basal sliding, where the base of the glacier is lubricated by meltwater, allowing the glacier to slide over the terrain on which it sits. Meltwater may be produced by pressure-induced melting,

neg: Icefall Icefall Perhaps the most conspicuous consequence of glacier flow, icefalls occur where the glacier bed steepens and/or narrows. Most glacier ice flows at speeds of a few hundred metres per year or less. However, the flow of ice in an icefall may be measured in kilometres per year. Such rapid flow cannot be accommodated by plastic deformation of the ice. Instead, the ice fractures forming crevasses. Intersecting fractures form ice columns or seracs. These processes are imperceptible for the most part; however, a serac may collapse or topple abruptly and without warning. This behavior often poses the biggest risk to

neg: Lambert Glacier a steep escarpment. The ice-fall which so impressively illustrates the flow characteristics of glacier ice is only about 6 km wide, and Lambert Glacier proper is off the bottom right corner of the photo. The ice here is flowing at about 500 m per year, but velocities of over 1200 m per year are known at the edge of the Amery Ice Shelf, which is fed by this gigantic stream of ice. On the lower photo north is at the bottom, and the ice velocities are approximately as follow: Lambert Glacier Lambert Glacier is a major glacier in East Antarctica.

neg: Mount Rainier combined action of sliding over the rock on which they lie and by deformation, the gradual displacement between and within individual ice crystals. Maximum speeds occur near the surface and along the centerline of the glacier. During May 1970, Nisqually Glacier was measured moving as fast as per day. Flow rates are generally greater in summer than in winter, probably due to the presence of large quantities of meltwater at the glacier base. The size of glaciers on Mount Rainier has fluctuated significantly in the past. For example, during the last ice age, from about 25,000 to about 15,000 years

neg: Hemodynamics of the aorta to create the control volume. A common software used to construct the geometry and discretize the mesh is ANSYS. The inlet is identified as the cross section directly above the aortic valve. The outlets are identified as the brachiocephalic artery, left and right common carotid artery, subclavian artery, and the descending aorta. In order to replicate the flow velocities that occur in individual patients a PC-MRI is taken. The PC-MRI can be taken be 1D, 3D, or 4D. 1D PC-MRIs only capture the velocity in one direction, typically axially with the inlet. A 4D PC-MRI can capture the axial through

neg: Components of jet engines larger in cross-section than the lip flow area, whereas at the intake design flight Mach number the two flow areas are equal. At high flight speeds the streamtube is smaller, with excess air spilling over the lip. Beginning around Mach 0.85, shock waves can occur as the air accelerates through the intake throat. Careful radiusing of the lip region is required to optimize intake pressure recovery (and distortion) throughout the flight envelope. Supersonic intakes exploit shock waves to decelerate the airflow to a subsonic condition at compressor entry. There are basically two forms of shock waves: A sharp-lipped version of

neg: Surge (glacier) may permit the glacier to slide. This explains why surging glaciers tend to cluster in certain areas. Meier and Post suggest that once mass accumulates to a critical point, basal melting begins to occur. This provides a buoyancy force, "lifting" the glacier from the bed and reducing the friction force. Surge (glacier) Glacial surges are short-lived events where a glacier can advance substantially, moving at velocities up to 100 times faster than normal. Surging glaciers cluster around a few areas. High concentrations of surging glaciers occur in Svalbard, the Canadian Arctic islands, Alaska and Iceland. In some glaciers, surges can

neg: Mach tuck and a single, central nacelle containing the cockpit and armament. It quickly accelerated to terminal velocity in a dive. The short stubby fuselage had a detrimental effect in reducing the critical Mach number of the 15% thick wing center section with high velocities over the canopy adding to those on the upper surface of the wing. Mach tuck occurred at speeds above Mach 0.65; the air flow over the wing center section became transonic, causing a loss of lift. The resultant change in downwash at the tail caused a nose-down pitching moment and the dive to steepen (Mach tuck). The

neg: Scramjet they have no mechanical means of compression, ramjets cannot start from a standstill, and generally do not achieve sufficient compression until supersonic flight. The lack of intricate turbomachinery allows ramjets to deal with the temperature rise associated with decelerating a supersonic flow to subsonic speeds, but this only goes so far: at near-hypersonic velocities, the temperature rise and inefficiencies discourage decelerating the flow to the magnitude found in ramjet engines. Scramjet engines operate on the same principles as ramjets, but do not decelerate the flow to subsonic velocities. Rather, a scramjet combustor is supersonic: the inlet decelerates the flow to

neg: Hummocky cross-stratification m) but with low height (10s of centimeters). Laminations drape these hummocks; in cross-section view, these laminations have an upward curvature, and low angle, curved intersections. Hummocky cross-stratification can form in sediments up to about 3 cm in diameter, with near-bed water particle velocities between about 40–100 cm/s. This structure is formed under a combination of unidirectional and oscillatory flow that is generated by relatively large storm waves in the ocean. Deposition involves fallout from suspension and lateral tractive flow due to wave oscillation. As the large waves drape sand over an irregular scoured surface, this strong storm-wave action erodes

neg: Hemodynamics in cm/s. This value is inversely related to the total cross-sectional area of the blood vessel and also differs per cross-section, because in normal condition the blood flow has laminar characteristics. For this reason, the blood flow velocity is the fastest in the middle of the vessel and slowest at the vessel wall. In most cases, the mean velocity is used. There are many ways to measure blood flow velocity, like videocapillary microscoping with frame-to-frame analysis, or laser Doppler anemometry. Blood velocities in arteries are higher during systole than during diastole. One parameter to quantify this difference is the "pulsatility

neg: Surge (glacier) Surge (glacier) Glacial surges are short-lived events where a glacier can advance substantially, moving at velocities up to 100 times faster than normal. Surging glaciers cluster around a few areas. High concentrations of surging glaciers occur in Svalbard, the Canadian Arctic islands, Alaska and Iceland. In some glaciers, surges can occur in fairly regular cycles, with 15 to 100 or more surge events per year. In other glaciers, surging remains unpredictable. In some glaciers, however, the period of stagnation and build-up between two surges typically lasts 10 to 200 years and is called the quiescent phase. During this period the

neg: History of ice drilling six flow markers in a line across the glacier, which Agassiz hoped would have moved by the following year, demonstrating the flow of the glacier. He believed in the dilatation theory of glacier flow, which argued that the refreezing of meltwater caused glaciers to progressively lengthen; this theory implied that the flow rate should be greatest where the water input was greatest. Agassiz returned to the Unteraargletscher in August 1841, this time equipped with a drill consisting of 10 iron rods, each long, of the kind used to drill for wells; a longer drill could not have been used by

neg: Surge (glacier) is important in reducing frictional forces to glacial ice flow. The distribution and pressure of water at the bed modulates the glacier's velocity and therefore mass balance. Meltwater may come from a number of sources, including supraglacial lakes, geothermal heating of the bed, conduction of heat into the glacier and latent heat transfers. There is a positive feedback between velocity and friction at the bed, high velocities will generate more frictional heat and create more meltwater. Crevassing is also enhanced by greater velocity flow which will provide further rapid transmission paths for meltwater flowing towards the bed. However, Humphrey found

neg: Kantrowitz limit The inclusion of a compressor in the Hyperloop pod circumvents the Kantrowitz limit, allowing the pod to travel at speeds over 700 mph in a relatively narrow tube. For a pod travelling through a tube, the Kantrowitz limit is given as the ratio of tube area to bypass area both around the outside of the pod and through any air-bypass compressor: Kantrowitz limit In gas dynamics, the Kantrowitz limit refers to a theoretical concept describing choked flow at supersonic or near-supersonic velocities. When a fluid flow experiences a reduction in area, the flow speeds up in order to maintain the

neg: Laminar flow diffusion and low momentum convection. When a fluid is flowing through a closed channel such as a pipe or between two flat plates, either of two types of flow may occur depending on the velocity and viscosity of the fluid: laminar flow or turbulent flow. Laminar flow tends to occur at lower velocities, below a threshold at which it becomes turbulent. Turbulent flow is a less orderly flow regime that is characterised by eddies or small packets of fluid particles, which result in lateral mixing. In non-scientific terms, laminar flow is "smooth", while turbulent flow is "rough". The type of

neg: Particle-size distribution If we start with low flow rates small less dense particle attain terminal velocities, and flow with the stream, the particle from the stream is collected in overflow and hence will be separated from the feed. Flow rates can be increased to separate higher size ranges. Further size fractions may be collected if the overflow from the first tube is passed vertically upwards through a second tube of greater cross-section, and any number of such tubes can be arranged in series. "Advantages": a bulk sample is analyzed using centrifugal classification and the technique is non-destructive. Each cut-point can be recovered

neg: Open channel spillway temperature remains constant. In the case of a dam spillway, this can be caused by turbulence or vortices in flowing water. Cavitation occurs within the body of flow of a given distributed roughness. However, the exact location where it will occur cannot be predicted. In the case of chute spillways, cavitation occurs at velocities between 12 and 15 m/s. When cavitation occurs on a spillway, it can cause severe damage. This is especially true when the velocities exceed 25 m/s. Therefore, protection is needed at these velocities. Cavitation can be prevented by decreasing the flow velocity or by increasing the

neg: Reynolds number developed" flow, laminar flow occurs when < 2300 and turbulent flow occurs when > 2900. At the lower end of this range, a continuous turbulent-flow will form, but only at a very long distance from the inlet of the pipe. The flow in between will begin to transition from laminar to turbulent and then back to laminar at irregular intervals, called intermittent flow. This is due to the different speeds and conditions of the fluid in different areas of the pipe's cross-section, depending on other factors such as pipe roughness and flow uniformity. Laminar flow tends to dominate in the

neg: Surge (glacier) which correlates to differences between the surging part of a glacier and the output of water and sediment. When the 1982 surge ended on July 5, there was a large flood event that day, and more flooding in the following days. What Humphrey found in his study is that behind the glacial surge zone, there are predominantly low basal water velocities, and high sliding rates before the rapid release of large quantities of water. There have been many theories of why glacial surges occur. Surges may be caused by the supply of meltwater to the base of a glacier. Meltwater

neg: Supersonic transport high jet velocities used during take-off, and even more importantly flying over communities near the airport. SST engines need a fairly high specific thrust (net thrust/airflow) during supersonic cruise, to minimize engine cross-sectional area and, thereby, nacelle drag. Unfortunately this implies a high jet velocity, which makes the engines noisy which causes problems particularly at low speeds/altitudes and at take-off. Therefore, a future SST might well benefit from a variable cycle engine, where the specific thrust (and therefore jet velocity and noise) is low at take-off, but is forced high during supersonic cruise. Transition between the two modes would occur

neg: Kantrowitz limit Kantrowitz limit In gas dynamics, the Kantrowitz limit refers to a theoretical concept describing choked flow at supersonic or near-supersonic velocities. When a fluid flow experiences a reduction in area, the flow speeds up in order to maintain the same mass-flow rate, per the continuity equation. If a near supersonic flow experiences an area contraction, the velocity of the flow will increase until it reaches the local speed of sound, and the flow will be choked. This is the principle behind the Kantrowitz limit: it is the maximum amount of contraction a flow can experience before the flow chokes, and

neg: Nozzle for supersonic flight by using a CD nozzle despite weight and cost penalties; conversely, subsonic jet engines employ relatively low, subsonic, exhaust velocities and therefore employ simple convergent nozzle, or even bypass nozzles at even lower speeds. Rocket motors maximise thrust and exhaust velocity by using convergent-divergent nozzles with very large area ratios and therefore extremely high pressure ratios. Mass flow is at a premium because all the propulsive mass is carried with vehicle, and very high exhaust speeds are desirable. Magnetic nozzles have also been proposed for some types of propulsion, such as VASIMR, in which the flow of

neg: Surge (glacier) velocities of the glacier are significantly lower, and the glaciers can retreat substantially. Glacier surges have been divided into two categories depending on the character of the surge event. Glaciers in Alaska exhibit surges with a sudden onset, extremely high (tens of meters/day)maximum flow rate and a sudden termination, often with a discharge of stored water. These are called Alaskan-type surges and it is suspected that these surges are hydrologically controlled. Surges in Svalbard typically exhibit different behavior. Svalbard surges are typically associated with slower onset with an acceleration phase, rising to a maximum velocity which is typically slower (up

neg: Swash where swash is characterised by standing long-wave motion. Values εb<2.5 indicate reflective conditions where swash is dominated by wave bores. Swash consists of two phases: uprush (onshore flow) and backwash (offshore flow). Generally uprush velocities are greater but of shorter duration compared to the backwash. Onshore velocities are at greatest at the start of the uprush and then decrease, whereas offshore velocities increase towards the end of the backwash. The direction of the uprush varies with the prevailing wind, whereas the backwash is always perpendicular to the coastline. This asymmetrical motion of swash can cause longshore drift as well as

neg: Hagen–Poiseuille equation equation are that the fluid is incompressible and Newtonian; the flow is laminar through a pipe of constant circular cross-section that is substantially longer than its diameter; and there is no acceleration of fluid in the pipe. For velocities and pipe diameters above a threshold, actual fluid flow is not laminar but turbulent, leading to larger pressure drops than calculated by the Hagen–Poiseuille equation. In standard fluid-kinetics notation: where: The equation does not hold close to the pipe entrance. The equation fails in the limit of low viscosity, wide and/or short pipe. Low viscosity or a wide pipe may result

neg: Landslide in the Italian Alps (area ) affected by a debris flow, estimated a peak discharge of for a section located in the middle stretch of the main channel. At the same cross section, the maximum foreseeable water discharge (by HEC-1), was , a value about 40 times lower than that calculated for the debris flow that occurred. An Earthflow is the downslope movement of mostly fine-grained material. Earthflows can move at speeds within a very wide range, from as low as to . Though these are a lot like mudflows, overall they are more slow moving and are covered with

neg: Halteres by maintaining that response until it is corrected (vision). Flies rely on both visual information from their compound eyes and mechanical input from their halteres. Sherman and Dickinson (2002) discovered that the responsiveness of the halteres and eyes are tuned to complimentary speeds of rotation. Responses to body rotations detected via the visual system are greatest at slow speeds and decrease with increased angular velocity. In contrast, body rotations detected by the halteres elicit the greatest responses at higher angular velocities and degrade as the speed of rotation decreases. The integration of these two separately tuned sensors allows the flies

neg: Meander irrotational flow: In real meandering rivers, we observe higher downstream fluid velocities at the outside bends. The higher (lower) velocities at the outside (inside) bend result in higher (lower) shear stresses and therefore results in erosion (deposition). Thus meander bends erode at the outside bend, causing the river to becoming increasingly sinuous (until cutoff events occur). Deposition at the inside bend occur such that for most natural meandering rivers, the river width remains nearly constant, even as the river evolves. The technical description of a meandering watercourse is termed meander geometry or meander planform geometry. It is characterized as an

neg: Tunnel valley glaciation provide a general mapping of the glacier thickness when the tunnel valleys were formed, particularly if the original surface relief under the glacier was limited. Analyses by Piotrowski demonstrate that the annual production of water from one typical catchment of would normally drain through its associated tunnel valley in less than 48 hours. The debris found in tunnels and at the mouth of tunnels tends to be coarse rocks and boulders – this is indicative of high flow velocities and an extremely erosive environment. This erosive environment is consistent with creation of tunnels over deep and wide, as have

neg: Sedimentary structures (multiple directions, back-and-forth) and unidirectional. Flow regimes in single-direction (typically fluvial) flow, which at varying speeds and velocities produce different structures, are called bedforms. In the "lower flow regime", the natural progression is from a flat bed, to some sediment movement (saltation etc.), to ripples, to slightly larger dunes. Dunes have a vortex in the lee side of the dune. As the "upper flow regime" forms, the dunes become flattened out, and then produce antidunes. At higher still velocity, the antidunes are flattened and most sedimentation stops, as erosion takes over as the dominant process. Typical unidirectional bedforms represent a

neg: First flush during peak flows. The wetted perimeter of sewers may also be colonized by biofilm nourished by soluble sanitary wastes. Hydraulic design is the underlying reason for solids deposition in sewers. Combined sewers sized for peak runoff events expected once a decade can carry up to 1,000 times the average sanitary flow. Less dramatically oversized sewers are common in new developments and near the upstream end of collection systems. Suspended solids may accumulate when low-flow fluid velocities generate insufficient turbulence. Solids deposition is greatest where velocities are low during dry weather. In large combined sewers it may be impossible to attain

neg: Ultrafiltration On the other hand in cross flow systems the flow passes parallel to the membrane surface. Dead-end configurations are more suited to batch processes with low suspended solids as solids accumulate at the membrane surface therefore requiring frequent backflushes and cleaning to maintain high flux. Cross-flow configurations are preferred in continuous operations as solids are continuously flushed from the membrane surface resulting in a thinner cake layer and lower resistance to permeation. Flow velocity is especially critical for hard water or liquids containing suspensions in preventing excessive fouling. Higher cross-flow velocities can be used to enhance the sweeping effect across

neg: Subsonic and transonic wind tunnel interactions occur (such as shock waves or boundary layer interaction) both Mach and Reynolds number are important and must be properly simulated. Large-scale facilities and/or pressurized or cryogenic wind tunnels are used. With a sonic throat, the flow can be accelerated or slowed down. This follows from the 1D area–velocity equation. If an acceleration to supersonic flow is required, a convergent-divergent nozzle is required. Otherwise: Conclusion: The Mach number is controlled by the expansion ratio formula_11 Subsonic and transonic wind tunnel Low-speed wind tunnels are used for operations at very low Mach number, with speeds in the test section up

neg: Tumble flap specifically produced air flow and a special geometry of the piston, while pure air is placed near the cylinder walls. Tumble flaps are used to realize this stratified charge. The flaps remain closed during the stratified charge mode. A switchable tumble system is normally used to direct a targeted air flow. The so-called "tumble plate" divides the air inlet channel into an upper and lower half. An upstream flap allows air flow either only over the upper part or over the entire cross-section. At higher engine speeds and torques, the tumble flap is opened to achieve a better degree of

neg: Northern Parkway (Arizona) Northern Parkway (Arizona) Northern Parkway is a major parkway in Maricopa County, Arizona in the United States. Northern Parkway is an enhanced arterial street with grade-separated intersections planned at major cross streets (from Sarival Avenue to El Mirage Road) to eliminate the major traffic signals originally found on Northern Avenue. The roadway has twice the traffic carrying capacity of a typical arterial and enables traffic to flow at average speeds of , as compared to typical arterials with average speeds around . Work on the section from Loop 303 to Dysart Road began in 2012 and was finished in January

neg: Maxwell–Boltzmann distribution to particle velocities in three dimensions, but turns out to depend only on the speed (the magnitude of the velocity) of the particles. A particle speed probability distribution indicates which speeds are more likely: a particle will have a speed selected randomly from the distribution, and is more likely to be within one range of speeds than another. The kinetic theory of gases applies to the classical ideal gas, which is an idealization of real gases. In real gases, there are various effects (e.g., van der Waals interactions, vortical flow, relativistic speed limits, and quantum exchange interactions) that can make

neg: High-speed flight an airplane. During flight, a wing produces lift by accelerating the airflow over the upper surface. This accelerated air can, and does, reach supersonic speeds, even though the airplane itself may be flying at a subsonic airspeed (Mach number < 1.0). At some extreme angles of attack, in some airplanes, the speed of the air over the top surface of the wing may be double the airplane’s airspeed. It is, therefore, entirely possible to have both supersonic and subsonic airflows on an airplane at the same time. When flow velocities reach sonic speeds at some locations on an airplane (such

neg: Tsunami earthquake associated with ordinary tsunamigenic earthquakes of the same moment magnitude, typically more than double. Rupture velocities for tsunami earthquakes are typically about 1.0 km per second, compared to the more normal 2.5–3.5 km per second for other megathrust earthquakes. These slow rupture speeds lead to greater directivity, with the potential to cause higher run-ups on short coastal sections. Tsunami earthquakes mainly occur at subduction zones where there is a large accretionary wedge or where sediments are being subducted, as this weaker material leads to the slower rupture velocities. Analysis of tsunami earthquakes such as the 1946 Aleutian Islands earthquake shows

neg: Synthetic jet of a hose. The water mixes with air to form a jet. If you increase the flow of water or move your thumb to change the diameter of the exit, the jet will change dramatically. Jet flows vary depending on velocity and diameter of the flow and the density and viscosity of the fluid (Reynolds number and Mach number). When the velocities in the jet are greater than the speed of sound, important qualitative changes in the flow occur. One such change is that shock waves form. A "synthetic jet flow" was so named by Ari Glezer since the flow

neg: Contourite dramatically or even reverse due to atmospheric storms raising the local surface eddy kinetic energy, which gets partially transmitted down to abyssal depths in episodes called benthic storms. These velocities may reach magnitudes well above 40 cm/s and vary significantly depending on the specific location. At the lower continental rise, south of Halifax, Nova Scotia, and at the lower slope around the Faeroe Islands these velocities may reach up to 73 cm/s and 75 cm/s, respectively. Bottom-current flow velocities have been measured as high as 300 cm/s in the Strait of Gibraltar. These benthic storms occur only 5 to 10

neg: Electro-osmosis Electro-osmosis Electroosmotic flow (or electro-osmotic flow, often abbreviated EOF; synonymous with electroosmosis or electroendosmosis) is the motion of liquid induced by an applied potential across a porous material, capillary tube, membrane, microchannel, or any other fluid conduit. Because electroosmotic velocities are independent of conduit size, as long as the electrical double layer is much smaller than the characteristic length scale of the channel, electroosmotic flow will have little effect. Electroosmotic flow is most significant when in small channels. Electroosmotic flow is an essential component in chemical separation techniques, notably capillary electrophoresis. Electroosmotic flow can occur in natural unfiltered water, as

neg: Kármán vortex street Kármán vortex street In fluid dynamics, a Kármán vortex street (or a von Kármán vortex street) is a repeating pattern of swirling vortices, caused by a process known as vortex shedding, which is responsible for the unsteady separation of flow of a fluid around blunt bodies. It is named after the engineer and fluid dynamicist Theodore von Kármán, and is responsible for such phenomena as the "singing" of suspended telephone or power lines and the vibration of a car antenna at certain speeds. A vortex street will only form at a certain range of flow velocities, specified by a range

neg: Kármán vortex street always oscillates.' " Kármán vortex street In fluid dynamics, a Kármán vortex street (or a von Kármán vortex street) is a repeating pattern of swirling vortices, caused by a process known as vortex shedding, which is responsible for the unsteady separation of flow of a fluid around blunt bodies. It is named after the engineer and fluid dynamicist Theodore von Kármán, and is responsible for such phenomena as the "singing" of suspended telephone or power lines and the vibration of a car antenna at certain speeds. A vortex street will only form at a certain range of flow velocities, specified

neg: D'Alembert's paradox high velocities and high Reynolds numbers, a no-slip boundary condition causes a strong variation of the flow speeds over a thin layer near the wall of the body. This leads to the generation of vorticity and viscous dissipation of kinetic energy in the boundary layer. The energy dissipation, which is lacking in the inviscid theories, results for bluff bodies in separation of the flow. The low pressure in the wake region causes form drag, and this can be larger than the friction drag due to the viscous shear stress at the wall. Evidence that Prandtl's scenario occurs for bluff bodies

neg: Scramjet the total pressure of the flow. Around Mach 3–4, turbomachinery is no longer useful, and ram-style compression becomes the preferred method. Ramjets utilize high-speed characteristics of air to literally 'ram' air through an inlet diffuser into the combustor. At transonic and supersonic flight speeds, the air upstream of the inlet is not able to move out of the way quickly enough, and is compressed within the diffuser before being diffused into the combustor. Combustion in a ramjet takes place at subsonic velocities, similar to turbojets, but the combustion products are then accelerated through a convergent-divergent nozzle to supersonic speeds. As

neg: Check valve the disc, the movable part to block the flow, swings on a hinge or trunnion, either onto the seat to block reverse flow or off the seat to allow forward flow. The seat opening cross-section may be perpendicular to the centerline between the two ports or at an angle. Although swing check valves can come in various sizes, large check valves are often swing check valves. A common issue caused by swing check valves is known as water hammer. This can occur when the swing check closes and the flow abruptly stops, causing a surge of pressure resulting in high

neg: Seitz Canyon The canyon then drops to the north as a spectacular headwall of over to a nearly level basin that includes Seitz Lake. It is here that the greatest evidence for glacial sculpturing can be found. The canyon shows a classic U-shaped cross section, and many patches of bare granite still retain the dark patina and striations caused by direct contact with the lower surface of the glacier that once filled this valley. From Seitz Lake the canyon makes a more gradual descent to its middle section , an area that includes a dense stand of aspen trees and beaver ponds.

neg: Laminar flow Laminar flow In fluid dynamics, laminar flow (or streamline flow) occurs when a fluid flows in parallel layers, with no disruption between the layers. At low velocities, the fluid tends to flow without lateral mixing, and adjacent layers slide past one another like playing cards. There are no cross-currents perpendicular to the direction of flow, nor eddies or swirls of fluids. In laminar flow, the motion of the particles of the fluid is very orderly with particles close to a solid surface moving in straight lines parallel to that surface. Laminar flow is a flow regime characterized by high momentum

neg: Cavitation the flow stream. If the pressure recovers after the valve to a pressure that is once again above the vapor pressure, then the vapor bubbles will collapse and cavitation will occur. When water flows over a dam spillway, the irregularities on the spillway surface will cause small areas of flow separation in a high-speed flow, and, in these regions, the pressure will be lowered. If the flow velocities are high enough the pressure may fall to below the local vapor pressure of the water and vapor bubbles will form. When these are carried downstream into a high pressure region the

neg: Aerodynamics density change occurs at the stagnation point (the point on the object where flow speed is zero), while the density changes around the rest of the object will be significantly lower. Transonic, supersonic, and hypersonic flows are all compressible flows. The term Transonic refers to a range of flow velocities just below and above the local speed of sound (generally taken as Mach 0.8–1.2). It is defined as the range of speeds between the critical Mach number, when some parts of the airflow over an aircraft become supersonic, and a higher speed, typically near Mach 1.2, when all of the

neg: De Laval nozzle isentropic (gas entropy is nearly constant). In a subsonic flow sound will propagate through the gas. At the "throat", where the cross-sectional area is at its minimum, the gas velocity locally becomes sonic (Mach number = 1.0), a condition called choked flow. As the nozzle cross-sectional area increases, the gas begins to expand and the gas flow increases to supersonic velocities where a sound wave will not propagate backwards through the gas as viewed in the frame of reference of the nozzle (Mach number > 1.0). A de Laval nozzle will only choke at the throat if the pressure and

neg: Langmuir circulation jets of downward flow form and the magnitude of the current will be comparable to the horizontal flow. The downward propagation will typically be in the order of meters or tenths of meters and will not penetrate the pycnocline. The upwelling is less intense and takes place over a wider band under the divergence zone. In wind speeds ranging from the maximum vertical velocity ranged from with a ratio of down-welling to wind velocities ranging from −0.0025 to −0.0085. Langmuir circulation In physical oceanography, Langmuir circulation consists of a series of shallow, slow, counter-rotating vortices at the ocean's surface aligned

neg: Time of flight be analyzed. In ultrasonic flow meter measurement, TOF is used to measure speed of signal propagation upstream and downstream of flow of a media, in order to estimate total flow velocity. This measurement is made in a collinear direction with the flow. In planar Doppler velocimetry (optical flow meter measurement), TOF measurements are made perpendicular to the flow by timing when individual particles cross two or more locations along the flow (collinear measurements would require generally high flow velocities and extremely narrow-band optical filters). In optical interferometry, the pathlength difference between sample and reference arms can be measured by TOF

neg: River at the front of the glacier. Because of the gradient in pressure due to the overlying weight of the glacier, such streams can even flow uphill. An intermittent river (or ephemeral river) only flows occasionally and can be dry for several years at a time. These rivers are found in regions with limited or highly variable rainfall, or can occur because of geologic conditions such as a highly permeable river bed. Some ephemeral rivers flow during the summer months but not in the winter. Such rivers are typically fed from chalk aquifers which recharge from winter rainfall. In England these

neg: Swash transport. Flow velocities, suspended sediment concentrations and suspended fluxes are at greatest at the start of the uprush when the turbulence is maximum. Then the turbulence dissipates towards the end of the onshore flow, settling the suspended sediment to the bed. In contrast, the backwash is dominated by the sheet flow and bedload sediment transport. The flow velocity increases towards the end of the backwash causing more bed-generated turbulence, which results in sediment transport near the bed. The direction of the net sediment transport (onshore or offshore) is largely governed by the beachface gradient. Longshore drift by swash occurs either

neg: Bridge scour for scour. If the flow contracts from a wide floodplain, considerable scour and bank failure can occur. Relatively severe constrictions may require regular maintenance for decades to combat erosion. It is evident that one way to reduce contraction scour is to make the opening wider. Local scour arises from the increased velocities and associated vortices as water accelerates around the corners of abutments, piers and spur dykes. The flow pattern around a cylindrical pier. The approaching flow decelerates as it nears the cylinder, coming to rest at the centre of the pier. The resulting stagnation pressure is highest near the

neg: Kantrowitz limit the flow speed can no longer be increased above this limit, independent of changes in upstream or downstream pressure. Assume a fluid enters an internally contracting nozzle at cross-section 0, and passes through a throat of smaller area at cross-section 4. A normal shock is assumed to start at the beginning of the nozzle contraction, and this point in the nozzle is referred to as cross-section 2. Due to conservation of mass within the nozzle, the mass flow rate at each cross section must be equal: For an ideal compressible gas, the mass flow rate at each cross-section can be

neg: Undertow (water waves) However, drowning may occur when swimmers exhaust themselves by trying unsuccessfully to swim directly against the flow. On the United States Lifesaving Association website it is noted that some uses of the word "undertow" are incorrect: Undertow (water waves) In physical oceanography, undertow is the under-current which is moving offshore when waves are approaching the shore. Undertow is a necessary and universal feature for almost any large body of water: it is a return flow compensating for the onshore-directed average transport of water by the waves in the zone above the wave troughs. The undertow's flow velocities are generally strongest

neg: Vortex engine In uninhabited areas, faster speeds might be permitted so the vortex can survive in faster ambient winds. Most of the unnamed numbered items are a system of internal louvers and water pumps to manage air velocities and heating as the engine starts. In early studies it was not absolutely clear that this could be made workable due to cross-wind disruption of the vortex. This motivated later studies with wind tunnel empirical validation of the CFD model, which conclude, "The full scale simulations subjected to cross wind show that the power generation capacity is not affected by the cross winds." (Diwakar

neg: Dry Mesa Quarry a possible antidune bedform composed of gravel and sand which indicates flow velocities as high as 200 cm/s (5 miles/hour). Measured bone volumes can be equated to flow velocities. These calculated bone volume velocities are in agreement with flow velocities determined from grain size and bedforms. The river flow direction, based upon bedform orientations and bone elongation statistics, was to the east-northeast. Geologic and taphonomic characteristics indicate a short transport distance for the bone accumulation (Richmond and Morris, 1999). Dry Mesa Quarry The Dry Mesa Dinosaur Quarry is situated in southwestern Colorado, United States, near the town of Delta. Its

neg: Ice-sheet dynamics consequences: firstly, the bed is better insulated, allowing greater retention of geothermal heat. Secondly, the increased pressure can facilitate melting. Most importantly, τ is increased. These factors will combine to accelerate the glacier. As friction increases with the square of velocity, faster motion will greatly increase frictional heating, with ensuing melting – which causes a positive feedback, increasing ice speed to a faster flow rate still: west Antarctic glaciers are known to reach velocities of up to a kilometre per year. Eventually, the ice will be surging fast enough that it begins to thin, as accumulation cannot keep up with

neg: Ram accelerator punctured by the projectile are used to isolate the propellant stages. Each section is filled with a different fuel-air mixture chosen so that later sections have higher speeds of sound. As such, the ram can be maintained at optimal speeds of Mach 3–5 (relative to the mixture that it travels through) during its entire acceleration period. Ram accelerators optimized to use supersonic combustion modes can generate even higher velocities (Mach 6-8) due to the ability to combust fuel that is still moving at supersonic speed. Scramjet projectiles were tested in the HARP project in the 1960s. The chief advantage of

neg: Ice-sheet dynamics Cavitation on the stoss side increases this pressure gradient, which assists flow. The flow of water under the glacial surface can have a large effect on the motion of the glacier itself. Subglacial lakes contain significant amounts of water, which can move fast: cubic kilometres can be transported between lakes over the course of a couple of years. This motion is thought to occur in two main modes: pipe flow involves liquid water moving through pipe-like conduits, like a sub-glacial river; sheet flow involves motion of water in a thin layer. A switch between the two flow conditions may be

neg: Tête Rousse Glacier the soil and rock broken away by the force of the rushing water, Vallot estimated that a weight of 500 million kilograms of material had borne down on the villages. He also warned that a repeat of water build-up was quite likely to occur, and that this would become more dangerous as time went on. He advocated the use of explosives to ensure a permanent flow of meltwater away from the glacier. In 1904 a second water pocket was discovered within the glacier, and a hole was drilled to drain away 22,000 cubic metres. Opinions have differed as to the

neg: Shear flow magnitude of the shear force - only the cross-section of the structure. The shear center always lies along the axis of symmetry, and can be found using the following method: By definition, shear flow through a section of thickness t is calculated using formula_1, where formula_2. Thus the equation for shear flow in a particular web section of the cross-section of a thin-walled structure (in this case symmetric across the x-axis) is: where In fluid mechanics, the term "shear flow" (or "shearing flow") refers to a type of fluid flow which is caused by forces, rather than to the forces

neg: Centrifugal micro-fluidic biochip cross section of the channel that generates the surface tension. The liquid flow will be held in a hydrophilic channel when the cross section suddenly becomes large, while the flow will be held when the cross section of hydrophobic channel suddenly shrinks. The siphon valve is simply based upon the siphon phenomenon. When the cross section of the channel is small enough, the liquid in the chamber is able to flow along the channel due to surface tension. Unlike hydrophilic or hydrophobic valves, surface tension acts as a pump in this model while centrifugal force acts as resistance instead. The

neg: Inlet cone goes supersonic a conical shock wave appears, emanating from the cone apex. The flow area through the shock wave decreases and the air is compressed. As the flight Mach number increases, the conical shock wave becomes more oblique and eventually impinges on the intake lip. For higher flight speeds a moving cone becomes necessary to allow the supersonic compression to occur more efficiently over a wider range of speeds. With increasing flight speed the cone is moved to the rear, or into the intake. Due to the shape of the cone surface and the internal duct surface the internal flow

neg: Ice-sheet dynamics friction or geothermal heat. The more variable the amount of melting at surface of the glacier, the faster the ice will flow. The top 50 meters of the glacier form the fracture zone, where ice moves as a single unit. Cracks form as the glacier moves over irregular terrain, which may penetrate the full depth of the fracture zone. Most of the important processes controlling glacial motion occur in the ice-bed contact—even though it is only a few meters thick. Glaciers will move by sliding when the basal shear stress drops below the shear resulting from the glacier's weight. For

neg: Venturi scrubber Figure 1 illustrates the classic venturi configuration. A venturi scrubber consists of three sections: a converging section, a throat section, and a diverging section. The inlet gas stream enters the converging section and, as the area decreases, gas velocity increases. Liquid is introduced either at the throat or at the entrance to the converging section. The inlet gas, forced to move at extremely high velocities in the small throat section, shears the liquid from its walls, producing an enormous number of very tiny droplets. Particle and gas removal occur in the diverging section as the inlet gas stream mixes with

neg: Borda–Carnot equation cross section 1, before the contraction, and cross section 3, the vena contracta at which the main flow is contracted most. But there are substantial losses in the flow expansion from cross section 3 to 2. These head losses can be expressed by using the Borda–Carnot equation, through the use of the coefficient of contraction "μ": with "A" the cross-sectional area at the location of strongest main flow contraction 3, and "A" the cross-sectional area of the narrower part of the pipe. Since "A" ≤ "A", the coefficient of contraction is less than one: "μ" ≤ 1. Again there is

neg: Outwash plain materials, like silt, being the most distantly re-deposited, whereas larger boulders are the closest to the original terminus of the glacier. An outwash plain might contain surficial braided stream complexes that rework the original deposits. They may also contain kettle lakes, locations where blocks of ice have melted, leaving a depression that fills with water. The flow pattern of glacial rivers across sandar is typically diffuse and unchannelized, but in situations where the glacial snout has retreated from the terminal moraine, the flow is more channelized. Sandurs are most common in Iceland, where geothermal activity beneath ice caps speeds up

neg: UTA Aerodynamics Research Center and hypersonic facilities. The low-speed wind tunnel is a closed-circuit, continuous flow tunnel with a 100 hp, variable frequency drive. The test section measures 0.6 by 0.9 meters and is capable of flow velocities up to 50 m/s. It is equipped with 3 and 6 component force balances and a PC-based multiplexed data acquisition system. Smoke visualization is also available. An auxiliary high pressure air supply enables the tunnel to be used for jet and surface blowing studies. The high Reynolds number transonic Ludwieg tube wind tunnel has a porous wall test section that measures 19.5 by . It is

neg: Glacier National Park (U.S.) found in the streams that flow through Glacier National Park. No permit is required to fish in park waters. The threatened bull trout must be released immediately back to the water if caught; otherwise, the regulations on limits of catch per day are liberal. Winter recreation in Glacier is limited. Snowmobiling is illegal throughout the park. Cross-country skiing is permitted in the lower altitude valleys away from avalanche zones. (image gallery)<br> Glacier National Park (U.S.) Glacier National Park is an American national park located in northwestern Montana, on the Canada–United States border, adjacent to the Canadian provinces of Alberta and

neg: Water tunnel (hydrodynamic) than imparting momentum on it directly. Thus the return section of water and oil tunnels does not need any flow management; typically it is just a pipe sized for the pump and desired flow speeds. The upstream section of a water tunnels generally consists of a pipe (outlet from the pump) with several holes along its side and with the end open followed by a series of coarse and fine screens to even the flow before the contraction into the test section. Wind tunnels may also have screens before the contraction, but in water tunnels they may be as fine

neg: Vatnajökull National Park glacier base reaches its lowest point 300 m below sea level. Nowhere in Iceland, with the exception of Mýrdalsjökull glacier, does more precipitation fall or more water drain to the sea than on the south side of Vatnajökull. In fact, so much water is currently stored in Vatnajökull that the Icelandic river with the greatest flow, Ölfusá, would need over 200 years to carry this quantity of water to sea. The scenery encircling the glacier is extremely varied. Towards the north, the highland plateau is divided by glacial rivers, with powerful flows in summer. The volcanoes of Askja, Kverkfjöll and

neg: Hagen–Poiseuille equation walls Therefore, the velocity distribution and the volume flow rate per unit length are Joseph Boussinesq derived the velocity profile and volume flow rate in 1868 for rectangular channel and tubes of equilateral triangular cross-section and for elliptical cross-section. Joseph Proudman derived the same for isosceles triangles in 1914. Let formula_21 be the constant pressure gradient acting in direction parallel to the motion. The velocity and the volume flow rate in a rectangular channel of height formula_40 and width formula_41 are The velocity and the volume flow rate of tube with equilateral triangular cross-section of side length formula_43 are The

neg: Stellar nucleosynthesis elements with even numbers of protons by the capture of helium nuclei. Elements with odd numbers of protons are formed by other fusion pathways. The reaction rate per volume between species "A" and "B", having number densities "n" is given by: where σ("v") is the cross section at relative velocity "v", and averaging is performed over all velocities. Semi-classically, the cross section is proportional to formula_2, where formula_3 is the de Broglie wavelength. Thus semi-classically the cross section is proportional to formula_4. However, since the reaction involves quantum tunneling, there is an exponential damping at low energies that depends on

neg: Superbubble wind bubbles merge, forming a giant bubble called a superbubble. When stars die, supernova explosions, similarly, drive blast waves that can reach even larger sizes, with expansion velocities up to several hundred km s. Stars in OB associations are not gravitationally bound, but they drift apart at small speeds (of around 20 km s), and they exhaust their fuel rapidly (after a few millions of years). As a result, most of their supernova explosions occur within the cavity formed by the stellar wind bubbles. These explosions never form a visible supernova remnant, but instead expend their energy in the hot

neg: Meteoroid Meteors may occur in showers, which arise when Earth passes through a stream of debris left by a comet, or as "random" or "sporadic" meteors, not associated with a specific stream of space debris. A number of specific meteors have been observed, largely by members of the public and largely by accident, but with enough detail that orbits of the meteoroids producing the meteors have been calculated. The atmospheric velocities of meteors result from the movement of Earth around the Sun at about , the orbital speeds of meteoroids, and the gravity well of Earth. Meteors become visible between about

neg: Tidal stream generator of tidal power generation. Tidal stream generators draw energy from water currents in much the same way as wind turbines draw energy from air currents. However, the potential for power generation by an individual tidal turbine can be greater than that of similarly rated wind energy turbine. The higher density of water relative to air (water is about 800 times the density of air) means that a single generator can provide significant power at low tidal flow velocities compared with similar wind speed. Given that power varies with the density of medium and the cube of velocity, water speeds of

neg: Bridge scour It is possible that both clear water and live-bed scour can occur. During a flood event, bed shear stress may change as the flood flows change. It is possible to have clear-water conditions at the commencement of a flood event, transitioning to a live bed before reverting to clear water conditions. Note that the maximum scour depth may occur under initial clear-water conditions, not necessarily when the flood levels peak and live-bed scour is underway. Similarly, relatively high velocities can be experienced when the flow is just contained within the banks, rather than spread over the floodplains at the peak

neg: Mount Adams (Washington) tumbles over some large cliffs to its diminutive lower section to the west. The White Salmon and Avalanche Glaciers feed the many streams of the Salt Creek and Cascade Creek drainages, which flow into the White Salmon River. The Pinnacle Glacier is the source of a fork of the Lewis River as well as Riley Creek, which is also a tributary of the Lewis River. The south side of the mountain along Suksdorf Ridge is moderately glacier-free, with the only glaciers being the relatively small Gotchen Glacier and the Crescent Glacier. The south side, however, does have some perennial snowfields

neg: Aerodynamic heating that other material replenishes the gases that have cooled to continue the process. The stagnation and the recovery temperature of a flow increases with the speed of the flow and are greater at high speeds. The total thermal loading of the object is a function of both the recovery temperature and the mass flow rate of the flow. Aerodynamic heating is greatest at high speed and in the lower atmosphere where the density is greater. In addition to the convective process described above, there is also Thermal radiation from the flow to the body and vice versa with the net

neg: Greenland ice sheet southeast of Thule. Large outlet glaciers, which are restricted tongues of the ice sheet, move through bordering valleys around the periphery of Greenland to calve off into the ocean, producing the numerous icebergs that sometimes occur in North Atlantic shipping lanes. The best known of these outlet glaciers is Jakobshavn Glacier (), which, at its terminus, flows at speeds of per day. On the ice sheet, temperatures are generally substantially lower than elsewhere in Greenland. The lowest mean annual temperatures, about , occur on the north-central part of the north dome, and temperatures at the crest of the south dome

neg: Variable geometry turbomachine Variable geometry turbomachine A variable geometry turbomachine uses movable vanes to optimize its efficiency at different operating conditions. This article refers to movable vanes as used in liquid pumps and turbocharger turbines. It does not cover the widespread use of movable vanes in gas turbine compressors. If all fluid velocities at corresponding points within the turbomachine are in the same direction and proportional to the blade speed, then the operating condition of a turbomachine at two different rotational speeds will be dynamically similar. If two points,each on dissimilar head-flow characteristics curve, represent similar dynamic operation of the turbo machine, then

neg: Waterfall over a large step in the rocks that may have been formed by a fault line. Waterfalls can occur along the edge of a glacial trough, where a stream or river flowing into a glacier continues to flow into a valley after the glacier has receded or melted. The large waterfalls in Yosemite Valley are examples of this phenomenon, which is referred to as a hanging valley. Another reason hanging valleys may form is where two rivers join and one is flowing faster than the other. Waterfalls can be grouped into ten broad classes based on the average volume of

neg: Borda–Carnot equation Borda–Carnot equation can be derived from mass- and momentum conservation of the flow. The momentum flux "S" (i.e. for the fluid momentum component parallel to the pipe axis) through a cross section of area "A" is – according to the Euler equations: Consider the conservation of mass and momentum for a control volume bounded by cross section 1 just upstream of the expansion, cross section 2 downstream of where the flow re-attaches again to the pipe wall (after the flow separation at the expansion), and the pipe wall. There is the control volume's gain of momentum "S" at the inflow

neg: Jökulhlaup glacier (supraglacially), below the glacier (subglacially/basally) or as groundwater in an aquifer below the glacier as a result of the hydraulic transmissivity of the subsoil under the glacier. If the rate of production exceeds the rate of loss through the aquifer, then water will collect in surface or subglacial ponds or lakes. The signatures of supraglacial and basal water flow differ with the passage zone. Supraglacial flow is similar to stream flow in all surface environments—water flows from higher areas to lower areas under the influence of gravity. Basal flow under the glacier exhibits significant differences. In basal flow the

neg: Traffic flow titled "Ideal Flow-Density Diagram". The figure "Ideal Flow-Density Diagram" shows there is a peak density that a roadway can sustain at an uncongested state, but if this density is surpassed then the roadway will fall into a congested traffic state. This density is known as the critical density, or KC. Shockwave theory is used in the VSL model to describe the effect of flow slow-down due to congestion. Shockwaves occur at the boundary between two different traffic flows, and their speeds can be shown as a ratio of a difference of density to the difference of volumes at the two

neg: Jakobshavn Glacier recently abandoned settlement of Sermermiut (which means 'place of the glacier people') lies just to the north of the glacier, much nearer than Ilulissat. The glacier is sometimes referred to as Ilulissat Glacier. This form simply replaces Jakobshavn with Ilulissat because of the change in the name of the town. Jakobshavn is one of the fastest moving glaciers, flowing at its terminus at speeds that used to be around per day but are currently over 45 metres (150 ft) per day when averaged annually, with summer speeds even higher. The speed of Jakobshavn Glacier varied between per year between 1992

neg: Flow in a Curb/Gutter System Flow in a Curb/Gutter System Ideal open channel flow can be observed via flow in a curb/gutter system. Such a system produces uniform flow that occurs at predictable times and provides easy access for measuring. The curb/gutter system cross section shape can be idealized as a triangular cross section. This project provides the details of a field exploration of flow in a curb/gutter system. The observed curb/gutter system is located on Hearthstone Drive in Blacksburg, Virginia. Located in an apartment complex parking lot, this system provides a segment of channel with a few imperfections. The segment totals 37 feet in

neg: Flow in a Curb/Gutter System located on Hearthstone Drive in Blacksburg, Virginia provided a useful exploration of an open channel system. When compared, the theoretical and observed computations maintained minimal relative error values. The curb.gutter system provided an excellent platformfor the confirmation of theoretical concepts. Flow in a Curb/Gutter System Ideal open channel flow can be observed via flow in a curb/gutter system. Such a system produces uniform flow that occurs at predictable times and provides easy access for measuring. The curb/gutter system cross section shape can be idealized as a triangular cross section. This project provides the details of a field exploration of flow

neg: Garibaldi Lake of the lake's water is due to glacial flour suspended in the meltwater from its two primary inflows, the large Sphinx Glacier to the east and the Sentinel Glacier to the south on the flanks of Mount Garibaldi. Throughout most of the year, outflow from Garibaldi Lake occurs only via seepage through cracks in the lava dam, with Rubble Creek appearing from springs at the base of The Barrier. During spring snowmelt, outflow is sufficient for surface drainage to occur via a shallow channel across the lava flow, into Lesser Garibaldi Lake and Barrier Lake about 1.6 km (1 mi)

neg: Tasman Glacier the lower parts are the Rudolf Glacier, Forrest Ross Glacier, Kaufmann Glacier, Haast Glacier, Hochstetter Glacier, and Ball Glacier. The glacial terminal lake is met by the meltwater of the Murchison Glacier, which approaches from the northeast and flows alongside the Tasman Glacier outside the moraine wall. The waters of Tasman Lake flow into the Tasman River and flow south joining the Hooker River draining the proglacial lakes on the Hooker and Mueller Glaciers. The Tasman River exhibits a braided characteristic, and flows south into Lake Pukaki. They eventually flow into the Waitaki River and to the Pacific Ocean north

neg: Tidewater glacier cycle (ELA) of a glacier. This is the imaginary line on a glacier, above which snow accumulates faster than it ablates, and below which, the reverse is the case. This altitude shift, in turn, prompts a retreat or advance of the terminus toward a new steady-state position. However, this change in terminus behavior for calving glaciers is also a function of resulting changes in fjord geometry, and calving rate at the glacier terminus as it changes position. Calving glaciers are different from land terminating glaciers in the variation in velocity along their length. Land terminating glacier velocities decline as the terminus

neg: Erebus Ice Tongue Indeed, British researchers in 2006 discovered a correlation between lunar tides (caused by gravitational pull) and variances in flow speed of the Rutland Ice Stream in Antarctica. Previously a team of U.S. NASA, Penn State, and University of Newcastle; Newcastle upon Tyne, England; made similar observations of Whillan's Ice Stream in Antarctica. However, more established research unrelated to lunar forces is available regarding cyclical glacier growth and decay. Such research reveals that glacier growth can produce slow-motion surges in the glacier's movement. Such surges may occur over a period of months or years. Then the movement stops. Scientists have measured

neg: Neutron cross section be to be consistent with this simple mechanical model. Cross sections depend strongly on the incoming particle speed. In the case of a beam with multiple particle speeds, the reaction rate "R" is integrated over the whole range of energy: Where "σ(E)" is the continuous cross section, "Φ(E)" the differential flux and "N" the target atom density. In order to obtain a formulation equivalent to the mono energetic case, an average cross section is defined: Where "Φ"= formula_18 "Φ(E) dE" is the integral flux. Using the definition of the integral flux "Φ" and the average cross section "σ", the same

neg: Byrd Polar and Climate Research Center Store Glacier in west Greenland. 2009 Jason Box installed time lapse cameras at Petermann Glacier in anticipation of a large area loss that eventually did occur August, 2010. 2010 April–May, 2010, Jason Box co-led a 750 km Arctic Circle Traverse across the southern Greenland ice sheet to obtain 3 ice cores and snow radar data to study spatial and temporal patterns of snowfall rates. BPRC scientists have obtained ice cores from multiple locations on the Antarctic Ice Sheet. The Transantarctic Mountains bisect the continental ice sheets, with different ice flow dynamics on either side. Radarsat (radar images collected by orbiting

neg: Cavitation bubbles collapse giving rise to high pressures and possible cavitation damage. Experimental investigations show that the damage on concrete chute and tunnel spillways can start at clear water flow velocities of between 12 and 15 m/s, and, up to flow velocities of 20 m/s, it may be possible to protect the surface by streamlining the boundaries, improving the surface finishes or using resistant materials. When some air is present in the water the resulting mixture is compressible and this damps the high pressure caused by the bubble collapses. If the flow velocities near the spillway invert are sufficiently high, aerators