Simulation and Modeling of the Elliptic Streamline Ow

Direct numerical simulations are performed for the elliptic streamline ow, which is a homogeneous turbulent ow that combines the eeects of solid body rotation and strain. Simulations are run over a range of parameters in order to determine the eeect of changing rotation and strain separately. For early times the nonlinear cascade is suppressed, but then is re-established at later times. The growth rate of turbulent kinetic energy agrees at early times with the trends from linear theory, but at later times the ow seems to approach an asymptotic state that is independent of the ratio of mean ow rotation rate to strain rate. A comparison with standard Reynolds stress turbulence models is made. It is found that for strong rotation rates, the models predict decay of the turbulence, while the simulations show exponential growth. Close examination of the simulation results shows that they are aaected by excessively low Reynolds numbers. Suggestions for reducing low Reynolds number eeects in future simulations is given.