Direct numerical simulation is used to investigate the decay exponent of isotropic homogeneous turbulence over a range of Reynolds numbers sufficient to display both high and low Re number decay behavior. The initial turbulence is generated by the stirring action of the flow past many small randomly placed cubes. Stirring occurs at 1/30th of the simulation domain size so that the low-wavenumber...

Many flows of practical interest occur at high Reynolds number, at which the flow in most of the boundary layer is turbulent, showing apparently random fluctuations in velocity across a wide range of scales. The range of scales over which these fluctuations occur increases with the Reynolds number and hence high Reynolds number flows are difficult to compute or predict. In this paper, we discus...

Global-stability theory is used to predict the onset of flow unsteadiness based on steady solutions of the Reynolds Averaged Navier–Stokes equations. The stability problem is formulated for compressible flow at moderately-high Reynolds numbers, using a turbulence model to provide closure for the averaged Reynolds stresses. The approach provides an efficient method for predicting the occurrence ...

The cross-stream migration of a deformable drop in two-dimensional Poiseuille flow at finite Reynolds numbers is studied numerically. In the limit of a small Reynolds number (<1), the motion of the drop depends strongly on the ratio of the viscosity of the drop fluid to the viscosity of the suspending fluid. For a viscosity ratio 0.125, the drop moves toward the centre of the channe while for t...

We study the driven cavity flow using the Navier slip boundary condition. Our results have shown that the Navier slip boundary condition removes the corner singularity induced by the no-slip boundary condition. In the low Reynolds number case, the behavior of the tangential stress is examined and the results are compared with the analytic results obtained in [14]. For the high Reynolds number, ...

the flow characteristics around an elliptic cylinder with an axis ratio of ar=2 located near a flat plate were investigated experimentally. the elliptic cylinder was located on the inside and outside a turbulent boundary layer region whose thickness (δ) is 0.38b. the reynolds numbers based on the height of the cylinder cross-section were 15000 and 30000. measurements of mean velocity and turbul...

High-order methods have demonstrated their potential in large eddy simulations (LES) of turbulent flows with relatively low Reynolds numbers. The cost becomes a serious limiting factor for high Reynolds number problems. A promising approach to reduce the cost of these simulations is the hybrid Reynolds-Averaged Navier-Stokes (RANS)/LES approach. In this paper, a new hybrid RANS-Implicit LES (IL...