Hele-Shaw flow

About: Hele-Shaw flow is a research topic. Over the lifetime, 5451 publications have been published within this topic receiving 151320 citations.

Stability of two-layer viscous stratified flow down an inclined plane.

Abstract: The stability of flow down an inclined plane is investigated for the case of a stratified fluid system consisting of two layers of viscous fluids of different densities. This problem is an extension of the works of Benjamin and Yih for a homogeneous fluid; thus their results are a special case of the solution for this more general problem. Reynolds numbers for the bifurcation point of the neutral curve are found for various ratios of density and depth of the two layers. For the purpose of comparing the relative stability between different configurations, a stability index is defined. It is found that the two‐layer flow is more stable or unstable than the homogeneous case of equal total depth, depending on whether the upper fluid is lighter or heavier than the lower one.

The dynamics of turbulent, transitional and laminar clay-laden flow over a fixed current ripple.

Abstract: Most aqueous sedimentary environments contain varying concentrations of fine-grained, often clay-rich, sediment that is transported in suspension and may modify the properties of the flow and underlying mobile bed. This paper presents results from a series of laboratory experiments examining the mean and turbulent properties of clay-laden (kaolinite) flows, of various volumetric sediment concentrations between 0·046% and 12·7%, moving over a fixed, idealized current ripple. As the kaolinite concentration was raised, with flow velocity and depth constant, four flow types were observed to occur: (i) turbulent flow, in which flow separation is dominant in the leeside of the ripple; (ii) turbulence-enhanced transitional flow, in which turbulence in the leeside separation zone region is enhanced; (iii) turbulence-attenuated transitional flow, in which turbulence along the separation zone shear layer and in the free flow above it becomes damped, eventually leading to a reduction in the size of the separation zone wake region; and (iv) laminar plug flow, in which turbulence is damped and flow is almost stagnant in the lee of the ripple. Such modulation of turbulence by increasing clay concentrations suggests that many paradigms of flow and bedform dynamics, which have been based on extensive past work in clear water flows, require revision. The present results highlight a need to fully characterize the boundary conditions for turbulence modulation as a function of clay type and applied flow conditions, and the effects of such flows on fully mobile cohesionless beds.

The turbulent mean-flow, Reynolds-stress, and heat flux equations in mass-averaged dependent variables

Abstract: The time-dependent, turbulent mean-flow, Reynolds stress, and heat flux equations in mass-averaged dependent variables are presented. These equations are given in conservative form for both generalized orthogonal and axisymmetric coordinates. For the case of small viscosity and thermal conductivity fluctuations, these equations are considerably simpler than the general Reynolds system of dependent variables for a compressible fluid and permit a more direct extension of low speed turbulence modeling to computer codes describing high speed turbulence fields.