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Flow separation
About: Flow separation is a research topic. Over the lifetime, 16708 publications have been published within this topic receiving 386926 citations.
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202 citations
TL;DR: In this paper, four different turbulence models were employed to study their influence on the results of pulsatile turbulent flow in axisymmetric stenoses and it was found that the low Reynolds number k-omega turbulence model was in much better agreement with previous experimental measurements than both the low and high Reynolds number versions of the RNG (renormalization-group theory) k-epsilon turbulence model and the standard k-EPsilon model, with regard to predicting the mean flow distal to the stenosis including aspects of the vortex shedding process and the turbulent flow
Abstract: Pulsatile turbulent flow in stenotic vessels has been numerically modeled using the Reynolds-averaged Navier-Stokes equation approach. The commercially available computational fluid dynamics code (CFD), FLUENT, has been used for these studies. Two different experiments were modeled involving pulsatile flow through axisymmetric stenoses. Four different turbulence models were employed to study their influence on the results. It was found that the low Reynolds number k-omega turbulence model was in much better agreement with previous experimental measurements than both the low and high Reynolds number versions of the RNG (renormalization-group theory) k-epsilon turbulence model and the standard k-epsilon model, with regard to predicting the mean flow distal to the stenosis including aspects of the vortex shedding process and the turbulent flow field. All models predicted a wall shear stress peak at the throat of the stenosis with minimum values observed distal to the stenosis where flow separation occurred.
201 citations
TL;DR: In this paper, a cell-centered finite volume formulation using an accurate linear reconstruction scheme and upwind flux differencing is presented for solving the Navier-Stokes equations for turbulent flow problems on three-dimensional unstructured grids.
Abstract: A method is presented for solving the Navier-Stokes equations for turbulent flow problems on three-dimensional unstructured grids. Spatial discretization is accomplished by a cell-centered, finite volume formulation using an accurate linear reconstruction scheme and upwind flux differencing. Time is advanced by an implicit backward Euler time-stepping scheme. Flow turbulence effects are modeled by the Spalart-Allmaras one-equation model, which is coupled with a wall function to reduce the number of cells in the sublayer region of the boundary layer. A systematic assessment of the method is presented to devise guidelines for more strategic application of the technology to complex problems. The assessment includes the accuracy in predictions of the skin-friction coefficient, law-of-the-wall behavior, and surface pressure for a flat-plate turbulent boundary layer and for the ONERA M6 wing under a high-Reynolds-number, transonic, separated flow condition
201 citations
TL;DR: Turbulent boundary layers along a convex surface of varying curvature were investigated in a specially designed boundary-layer tunnel as discussed by the authors, where a fairly complete set of turbulence measurements was obtained.
Abstract: Turbulent boundary layers along a convex surface of varying curvature were investigated in a specially designed boundary-layer tunnel. A fairly complete set of turbulence measurements was obtained. The effect of curvature is striking. For example, along a convex wall the Reynolds stress is decreased near the wall and vanishes about midway between the wall and the edge of a boundary layer where there exists a velocity profile gradient created upstream of the curved wall.
201 citations
200 citations