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Velocity gradient

About: Velocity gradient is a research topic. Over the lifetime, 3013 publications have been published within this topic receiving 77120 citations.


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Journal ArticleDOI
TL;DR: An explicit and simple approximation for the superadiabatic excess (over ideal gas) free power functional is presented, admitting the study of the nonequilibrium dynamics of overdamped Brownian many-body systems.
Abstract: We present an explicit and simple approximation for the superadiabatic excess (over ideal gas) free power functional, admitting the study of the nonequilibrium dynamics of overdamped Brownian many-body systems. The functional depends on the local velocity gradient and is systematically obtained from treating the microscopic stress distribution as a conjugate field. The resulting superadiabatic forces are beyond dynamical density functional theory and are of a viscous nature. Their high accuracy is demonstrated by comparison to simulation results.

48 citations

Journal ArticleDOI
TL;DR: In this article, the root-mean-square fluctuating mass transfer coefficient and the frequency spectrum of the fluctuating Mass Transfer coefficient for a Schmidt number of about 2300 were measured.
Abstract: Turbulent mass transfer to a wall at high Schmidt numbers is controlled by the velocity field within the viscous sublayer. Measurements have been obtained of the root-mean-square fluctuating mass transfer coefficient and the frequency spectrum of the fluctuating mass transfer coefficient for a Schmidt number of about 2300. From an order-of-magnitude analysis it is concluded that flow fluctuations in the direction of mean flow have little effect on the mass transfer fluctuations. A comparison of the mass transfer spectrum with the spectrum of the component of the velocity gradient in the transverse direction sz reveals that the high-frequency portion of the sz spectrum is not effective in transferring mass. Approximate relations between the mass transfer spectrum and the sz spectrum are developed for high frequencies and for low frequencies.

48 citations

Journal ArticleDOI
TL;DR: In this article, the effects of free stream turbulence and velocity gradient on film cooling effectiveness were analyzed via line sink models and correlations based on an energy balance, the latter was much more successful in describing the film cooling measurements.

48 citations

Journal ArticleDOI
TL;DR: In this paper, a series of experiments have been performed in order to analyze the shear orientation effect on a micellar cubic phase using small-angle x-ray-scattering techniques.
Abstract: A series of experiments has been performed in order to analyze the shear orientation effect on a micellar cubic phase using small-angle x-ray-scattering techniques. In a Couette cell, an oscillating shear of strain amplitude less than unity was applied to the crystal. Using a x-ray synchrotron beam, the reciprocal planes perpendicular to the flow velocity and velocity gradient, respectively, were probed. Length and angle correlations were well characterized in both planes and full separation of twinned fcc single crystals was evidenced in some cases, each of them being coherent at millimeter scale.

48 citations

Journal ArticleDOI
TL;DR: In this article, a nonlinear least squares inversion of traveltime data is applied to the problem of determining thicknesses, velocities, and velocity gradients in laterally homogeneous, horizontally layered structures.
Abstract: Nonlinear least‐squares inversion of traveltime data is applied to the problem of determining thicknesses, velocities, and velocity gradients in laterally homogeneous, horizontally layered structures. The parametric forms of the traveltime equations are used for the calculations. Results of inversions on randomly inaccurate synthetic data show that the method will not determine the gradient consistently when using reflection traveltimes. Good results are obtained, however, when using traveltimes of energy refracted in a layer by the velocity gradient. Thicknesses and average velocity in the case of reflections, or velocity at the top of the layer in the case of refractions, are also determined. Partial derivatives determined during the course of the least‐squares inversion can be used to place limits on errors in the determined parameters.

48 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202318
202233
2021127
2020116
2019134
201892