Last edited by Maur
Saturday, July 25, 2020 | History

2 edition of Shear dispersion in time-varying flows. found in the catalog.

Shear dispersion in time-varying flows.

W. C. Thacker

Shear dispersion in time-varying flows.

by W. C. Thacker

  • 118 Want to read
  • 21 Currently reading

Published by Environmental Research Laboratories, Atlantic Oceanographic and Meteorological Laboratories in Boulder, Colo .
Written in English

    Subjects:
  • Shear (Mechanics) -- Mathematical models.,
  • Shear flow.

  • Edition Notes

    Bibliography: p. 7.

    SeriesNOAA technical report ; ERL 386-AOML 27, NOAA technical report ERL -- 27., NOAA technical report ERL -- 386.
    ContributionsAtlantic Oceanographic and Meteorological Laboratories.
    The Physical Object
    Pagination7 p. :
    ID Numbers
    Open LibraryOL18224570M

    A single, non‐Brownian fiber suspended in a viscous, Newtonian fluid undergoing simple shear flow rotates in one of a set of closed orbits known as Jeffery orbits. In a fiber suspension, the hydrodynamic interactions among the fibers determine the distribution of fibers among these orbits. The hydrodynamic interactions in dilute and semidilute suspensions have been studied . The longitudinal dispersion due to the shear effect of a current is examined theoretically in the idealized two-dimensional case. This study reveals the process whereby the dispersion reaches a stationary stage after the release of the dispersing substance as an instantaneous line source in steady and in oscillatory currents.

    Chapter 4 - Turbulent shear flows Chapter 5 - Diffusion: basic theory Chapter 6 - Advective diffusion Chapter 7 - Turbulent dispersion and mixing. (1)Vertical and transverse mixing Chapter 8 - Turbulent dispersion and mixing. (2) Longitudinal dispersion Chapter 9 - Turbulent dispersion in natural systems.   In this paper the breakup of droplets under shear in polymer blends is studied by means of linear conservative dichroism and small angle light scattering. More specifically breakup of long fibrils by interfacial instabilities is considered. Measurements are performed on dilute model systems containing nearly Newtonian components in transient flows that involve a .

    P. M. Rightley, “Bubble dispersion and interphase coupling in a free shear flow,” Ph.D. thesis, University of California, San Diego, Google Scholar; K. Tio and J. C. Lasheras, “The dynamics of a small spherical particle in steady, two-dimensional vortex flows,” in AIAA/SAE/ASME/ASEE 29th Joint Propulsion Conference and Exhibit. Part of the SpringerBriefs in Applied Sciences and Technology book series LES of Particle Dispersion and Gas-to-Particle Mass Transfer in Turbulent Shear Flows. Sean C. Garrick, Michael Bühlmann.


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Shear dispersion in time-varying flows by W. C. Thacker Download PDF EPUB FB2

Shear flow → Shear dispersion Dispersion is simply another word for diffusion; but with a specific meaning. We use the word dispersion to describe a pr ocess that appears as diffusion but does not exactly proceed according to Fick's law (i.e., with a flux proportional to the concentration gradient).

The necessary ingredients for this process. An analysis is presented of the shear dispersion in turbulent channel flow forced by a purely oscillatory pressure gradient. The flow is described by an algebraic eddy viscosity model in which the instantaneous flow and viscosity are inter-dependent.

Both eddy viscosity and eddy diffusivity contain a second-harmonic time-varying by:   Shear dispersion in time varying flows was shown to be parameterizable as effective diffusion with a time varying diffusivity. This parameterization was appropriate only for time along in comparison with the cross shear mixing time.

High frequency variations of the flow did not contribute substantially to the mixing. Low frequency variations of the flow were Cited by: 1. the application of shear dispersion to mixing of passive and active scalars in rivers and estuaries. An example is shear dispersion of salt in which the shear flow is created by salinity gradients.

Other examples include fixed flux convection. INTRODUCTION InTaylor published a remarkable paper on the. Figure ms illustrating the evolution of a single Fourier component of a passive anomaly for (a) uniform laminar shear flow and (b) stagnation point flow, based on Figures 4 and 5 of Olson et al.

(b).The velocity field u is sketched for each case. In a uniform shear flow (a), the Fourier component is rotated into the direction of shear, while its wavelength decreases, such. Two types of shear experiments were used to carry out dispersion experiments. In one, a steady simple-shear flow was generated in a cone-and-plate device (CPD) that is depicted schematically in Fig.

-varying simple shear flow was applied in an oscillatory shear device (OSD) shown in Fig. s of these instruments can be found elsewhere.

The dispersion of marked fluid in turbulent shear flow - Volume 5 Issue 4 - J. Elder. The same analysis can be used to describe the longitudinal dispersion of discrete particles, both of zero buoyancy and of finite buoyancy, and comparison is made with observations by Batchelor, Binnie & Phillips () and Binnie & Phillips ().

Among all the inviscid models proposed in the literature, only the one developed by ONERA takes into account the 2D nature of the mean flow and the radial deformation of the entropy waves through the nozzle, which plays a crucial role in noise generation (Emmanuelli et al., J.

Sound Vib., vol.pp. This model has been. This is the second edition of the book “Thermodynamics of Fluids under Flow,” which was published in and has now been corrected, expanded and updated.

This is a companion book to our other title. The book introduces readers to and summarizes the current ideas and theories about the basic mechanisms for transport in chaotic flows. Typically no. This paper describes some laboratory and numerical experiments made on the longitudinal dispersion in an open channel flow.

Particular attention has been paid to the initial stages of the process. Physical arguments suggest that the streamwise dispersion of a line of marked fluid elements across a two-dimensional turbulent shear flow occurs in.

Simulations of spray and particle‐laden flows have commonly relied on random walk models to represent dispersion of liquid or solid particles by turbulent motions in the carrier fluid. Particles respond, through a Lagrangian equation of motion, to the mean fluid velocity, computed simultaneously from an Eulerian solution, and to a random fluctuation velocity.

The problem of shear dispersion in the atmospheric boundary layer (ABL) is revisited. The aim is to improve understanding of how and why the behaviour of state‐of‐the‐art ‘random flight’ Lagrangian particle dispersion models (RFMs) can differ from that of simpler ‘random displacement’ models (RDMs or eddy diffusivity models).

Experiments conducted in time‐varying flows further corroborated the results obtained in tensile cohesivity tests. Experiments in which the mean and maximum stresses in the time‐varying flows were matched to the stresses produced in steady shear flows highlight the influence of flow dynamics on dispersion behavior.

Purchase Air Bubble Entrainment in Free-Surface Turbulent Shear Flows - 1st Edition. Print Book & E-Book. ISBNused for systems with shear-dispersion dominating longitudinal diffusion (as in 20).

As one might expect, (16) shows that the coefficient of shear dispersion increases with the magnitude of the shear, expressed as the magnitude of the spatial deviations u'.

The dependence KX ~ h is less straight-forward. However, considering that each integral is. @article{osti_, title = {Shear dispersion in dense granular flows}, author = {Christov, Ivan C.

and Stone, Howard A.}, abstractNote = {We formulate and solve a model problem of dispersion of dense granular materials in rapid shear flow down an incline. The effective dispersivity of the depth-averaged concentration of the dispersing powder is shown to vary as.

Search the world's most comprehensive index of full-text books. My library. In a recent paper [Phys. Flu ()] we presented the results of our direct numerical simulations (DNS) study of the two-way coupling effects of solid particles dispersed in a homogeneous turbulent shear flow.

The objective of that study was to describe the physical mechanism associated with two-way coupling. Here, we present a DNS study of the dispersion. Shear Dispersion Dispersion in Parallel Shear Flow Evolution of the Spatial Variance Average Concentration Center of Mass Spatial Variance Infinitely Deep Channel Dispersion in Shallow Water Vertical Mixing in Open Channels.

Shear Dispersion Shear flow In the preceding sections, we restricted our attention to advection by uni-form flows. While a uniform flow causes a mere translation of the pollutant (transport without distortion), a non-uniform flow can produce new and im-portant effects. The cause is the differential advection: Different parts of the.A closed-form solution for longitudinal dispersion in this flow field is derived, which is an addition of the steady flow dispersion in the two regions and the dispersion caused by inefficient exchange between the two regions.appropriate shear stress or shear rate allows for a more relevant comparison [1,2].

This point is illustrated in figure 1 which shows a flow curve and the corresponding shear rate ranges associated with various processes. All of the listed processes are important, albeit to different extents, and the ideal.