Mass flow and velocity profiles in Neurospora hyphae: partial plug flow dominates intra-hyphal transport

Intense deformation within an extensive englacial debris layer appears to be a dominant flow mechanism for glaciers on Mount St Helens, Washington. Observations of this phenomenon have been made on Shoestring Glacier and more recently on other glaciers on the volcano. Transverse velocity profiles on Shoestring Glacier have shown a marked plug flow behavior occurring between narrow marginal zones of crevassing. Both longitudinal and transverse velocity profiles on Shoestring Glacier were measured during the year before and the two years after the cataclysmic eruption of the volcano on 18 May 1980. The geometry and regime of every glacier on Mount St Helens dramatically changed during the eruption. The entire accumulation area of Shoestring Glacier was removed by a volcanic landslide and blast, and the glacier surface was deeply incised through the action of pyroclastic flows and mudflows. Surface velocity measurements were supplemented by vertical profiles taken along the newly exposed ice cliffs. Large velocity gradients seen in the transverse, longitudinal and vertical profiles coincided with the mapped location of a recently exposed englacial debris layer. Further detailed measurements on the vertical profiles show that the intense shear occurs by deformation internal to the debris layer, A study of the properties of debris-laden ice was undertaken to determine the mechanism for localization of deformation to the debris layer and for the associated response of the glacier to a sudden change in stress.

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Properties of Debris-Laden Ice: Application to the Flow Response of the Glaciers on Mount St Helens

Annals of Glaciology ◽

10.3189/s0260305500005668 ◽

1983 ◽

Vol 4 ◽

pp. 297-297 ◽

Cited By ~ 2

Author(s):

Melinda M. Brugman

Keyword(s):

Flow Behavior ◽

Transverse Velocity ◽

Plug Flow ◽

Sudden Change ◽

Velocity Profiles ◽

Pyroclastic Flows ◽

Surface Velocity ◽

Vertical Profiles ◽

Glacier Surface ◽

Mount St Helens

Intense deformation within an extensive englacial debris layer appears to be a dominant flow mechanism for glaciers on Mount St Helens, Washington. Observations of this phenomenon have been made on Shoestring Glacier and more recently on other glaciers on the volcano. Transverse velocity profiles on Shoestring Glacier have shown a marked plug flow behavior occurring between narrow marginal zones of crevassing. Both longitudinal and transverse velocity profiles on Shoestring Glacier were measured during the year before and the two years after the cataclysmic eruption of the volcano on 18 May 1980.The geometry and regime of every glacier on Mount St Helens dramatically changed during the eruption. The entire accumulation area of Shoestring Glacier was removed by a volcanic landslide and blast, and the glacier surface was deeply incised through the action of pyroclastic flows and mudflows. Surface velocity measurements were supplemented by vertical profiles taken along the newly exposed ice cliffs. Large velocity gradients seen in the transverse, longitudinal and vertical profiles coincided with the mapped location of a recently exposed englacial debris layer. Further detailed measurements on the vertical profiles show that the intense shear occurs by deformation internal to the debris layer, A study of the properties of debris-laden ice was undertaken to determine the mechanism for localization of deformation to the debris layer and for the associated response of the glacier to a sudden change in stress.

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Calculation of Unsteady Flows in Curved Pipes

Journal of Fluids Engineering ◽

10.1115/1.1400748 ◽

2001 ◽

Vol 123 (4) ◽

pp. 869-877 ◽

Cited By ~ 24

Author(s):

H. A. Dwyer ◽

A. Y. Cheer ◽

T. Rutaganira ◽

N. Shacheraghi

Keyword(s):

Shear Stress ◽

Wall Shear Stress ◽

Mass Flow ◽

Numerical Solutions ◽

Stokes Equations ◽

Velocity Profiles ◽

Frequency Parameter ◽

Detailed Knowledge ◽

Curved Pipes ◽

Wall Shear

Highly unsteady three-dimensional flows in curved pipes with significant variation of flow geometry and flow parameters are studied. Using improvements in computational efficiency, detailed knowledge concerning flow structures is obtained. The numerical solutions of the Navier-Stokes equations have been obtained with a variation of the projection method, and the numerical method was enhanced by new algorithms derived from the physics of the flow. These enhancements include a prediction of the flow unsteady pressure gradient based on fluid acceleration and global pressure field corrections based on mass flow. This new method yields an order of magnitude improvement in the calculation’s efficiency, allowing the study of complex flow problems. Numerical flow simulations for oscillating flow cycles show that the curved pipe flows have a significant inviscid-like nature at high values of the frequency parameter. The shape of the velocity profiles is strongly influenced by the frequency parameter, whereas the influence of variations on the pipe cross-sectional area is shown to be rather weak. For large values of the frequency parameter the flow history strongly influences the low mass flow part of the cycle leading to highly unusual velocity profiles. The wall shear stress is studied for all the flows calculated. Our results show that wall shear stress is sensitive to area constrictions, the frequency parameter, as well as the shape of the entrance profile.

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Granular flow behavior in a conveyor system: From local velocity profiles to mass flow rates

Powder Technology ◽

10.1016/j.powtec.2020.12.062 ◽

2020 ◽

Author(s):

Hannah Higgins ◽

Michael Roeing-Donna ◽

Kamila Krupiarz ◽

Ryan O'Connor ◽

Jifu Tan ◽

...

Keyword(s):

Mass Flow ◽

Granular Flow ◽

Flow Behavior ◽

Velocity Profiles ◽

Local Velocity ◽

Flow Rates ◽

Conveyor System ◽

Mass Flow Rates

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Effect of Friction Coupling on Discharge Velocity Profiles and Force Chain Distribution of Maize Particles in Silos

Advances in Civil Engineering ◽

10.1155/2020/6655054 ◽

2020 ◽

Vol 2020 ◽

pp. 1-14

Author(s):

Yong Feng ◽

Caihua Yu ◽

Fan Pan

Keyword(s):

Mass Flow ◽

Vertical Velocity ◽

Rolling Friction ◽

Velocity Profiles ◽

Force Chain ◽

Discharge Velocity ◽

Maize Grain ◽

Interparticle Friction ◽

Funnel Flow ◽

Total Discharge

The evolution mechanism of discharge velocity profiles and force chain distribution of maize particles in silos was studied based on the interaction between internal and external rolling friction of particles. Through EDEM, the silo and maize grain models were established for unloading simulation, whose flow pattern was compared with the silo unloading test to verify the rationality of the simulation. By slice observation, we compared and analyzed the time evolution rules of particle mesoscopic parameters under different friction conditions. The results show that the larger the interparticle friction coefficient is, the longer the total discharge time is and the smaller the coefficient of rolling friction between particles, the earlier the particle flow from mass flow to funnel flow. For silos with the funnel, the reduction of interparticle friction will change the limit between the mass flow and the funnel flow, thus increasing the area of the funnel flow. When the coefficient of rolling friction increases, the vertical velocity and angular velocity of the particle near the silo middle increase. However, the effects of internal and external friction coupling on the vertical velocity of the side particle, the horizontal velocity of the whole particle, and the spatial distribution and probability distribution of the force chain are more significant.

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Atomization of Liquid by Two-Phase Gas-Liquid Flow Through a Nozzle

10.1115/imece2000-2053 ◽

2000 ◽

Author(s):

M. Lörcher ◽

D. Mewes

Keyword(s):

Mass Flow ◽

High Speed ◽

Droplet Diameter ◽

Critical Mass ◽

Bubbly Flow ◽

Plug Flow ◽

Volumetric Flow Rate ◽

Two Phase ◽

Equal Distribution ◽

The Mean

Abstract A liquid or a suspension is divided into small droplets by atomization. The mean goal is either the equal distribution of the droplets, or the generation of large surface areas of the liquid phase in order to increase heat- and mass-transfer. In two-phase atomization the spatial and time distribution of the mean droplet diameter of the spray depend on the total pressure upstream of the nozzle, the volumetric flow rate of the liquid and the gas, as well as on the flow regime in the nozzle. Thus the radial and axial profile of the void fraction inside the nozzle are measured with an electrical measurement technique. In addition, the flow in the nozzle is visualized by a high-speed camera. Three flow regimes are identified. These are bubbly flow, plug flow, and annular flow. At the smallest cross section of the nozzle critical mass flow is observed. A literature review on models to calculate the critical mass flow is given. The calculated and the measured mass flow rates are compared.

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