Topic
Velocity gradient
About: Velocity gradient is a research topic. Over the lifetime, 3013 publications have been published within this topic receiving 77120 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: In this article, the closed-loop Marangoni convection can be induced as a single convection cell at the air−water interface by means of continuous deposition of the surface tension-lowering solvent at the quiescent water surface.
Abstract: By means of continuous deposition of the surface tension-lowering solvent at the quiescent water surface, the closed-loop Marangoni convection can be induced as a single convection cell at the air−water interface For this single Marangoni convection cell, its temporal-spatial evolution is visualized by means of the shadowgraph optical method, and its surface radial velocity distribution is measured with the help of the high speed photography technique Meanwhile, an absorption experiment of CO2 into water, a scaling analysis, and a 2-D numerical simulation are conducted, respectively, to investigate mass transfer performance and flow characteristics of the induced Marangoni convection Results show that the induced Marangoni convection has the high surface velocity, the sharp velocity gradient is in the immediate vicinity of the water surface, and the velocity of the Marangoni convection in the bulk of water is much less than that near the interface The high surface velocity of the Marangoni convection
25 citations
22 Jul 2016
TL;DR: In this article, an experimental investigation of plane Couette flow under spanwise, anticyclonic system rotation was carried out and it was shown that there is a transport of the Reynolds shear stress towards the center of the channel, which may then result in a negative mean velocity gradient there.
Abstract: In an experimental investigation of plane Couette flow under spanwise, anticyclonic system rotation, analysis of the Reynolds stress transport equation shows that there is a transport of the Reynolds shear stress towards the center of the channel, which may then result in a negative mean velocity gradient there.
25 citations
TL;DR: In this article, the authors numerically calculate the hydrodynamic diffusion coefficients of a suspension of elastic capsules of viscosity ratio unity and as a function of volume fraction, elastic capillary number and channel height in a bounded simple shear flow.
Abstract: A suspension of red blood cells in a flow undergoes hydrodynamic or shear-induced diffusion. It is known from experiments that deoxygenated or stiffer red blood cells have a lower hydrodynamic diffusion coefficient compared to oxygenated or softer red blood cells. In this paper, we numerically calculate the hydrodynamic diffusion coefficients of a suspension of elastic capsules of viscosity ratio unity and as a function of volume fraction, elastic capillary number and channel height in a bounded simple shear flow. We show that the time required for the suspension to reach the diffusive regime in the direction perpendicular to the shear plane decreases with channel height. In a narrow channel, the effect of capsule elasticity is to delay the approach to a diffusive regime. However, the motion in the direction parallel to the velocity gradient is always subdiffusive. We show that the hydrodynamic diffusion coefficient in the direction perpendicular to the shear plane varies linearly with capsule volume fraction up to about 25%. In addition, it does not increase monotonously with elastic capillary number but drops when the capsules become sufficiently soft. Finally, it displays a weak dependence on the channel height.
25 citations
TL;DR: In this article, the propagation of elastic waves in heterogeneous sedimentary basins under incident SH plane waves is computed using the indirect boundary element method (IBEM), and the response of these basins by means of frequency-space diagrams, frequency-wave-number plots, synthetic seismograms, and snapshots of the displacements.
25 citations
TL;DR: In this article, an efficient, robust, and automatic method to fit ammonia lines with multiple velocity components, generalizable to other molecular species, has been presented, along with a complementary technique to sort fitted velocity components into velocity-coherent filaments.
Abstract: Recent observations of global velocity gradients across and along molecular filaments have been interpreted as signs of gas accreting onto and along these filaments, potentially feeding star-forming cores and proto-clusters. The behavior of velocity gradients in filaments, however, has not been studied in detail, particularly on small scales (< 0.1 pc). In this paper, we present MUFASA, an efficient, robust, and automatic method to fit ammonia lines with multiple velocity components, generalizable to other molecular species. We also present CRISPy, a Python package to identify filament spines in 3D images (e.g., position-position-velocity cubes), along with a complementary technique to sort fitted velocity components into velocity-coherent filaments. In NGC 1333, we find a wealth of velocity gradient structures on a beam-resolved scale of ~0.05 pc. Interestingly, these local velocity gradients are not randomly oriented with respect to filament spines and their perpendicular, i.e., radial, component decreases in magnitude towards the spine for many filaments. Together with remarkably constant velocity gradients on larger scales along many filaments, these results suggest a scenario in which gas falling onto filaments is progressively damped and redirected to flow along these filaments.
25 citations