Direct numerical simulation of turbulent flow over a rectangular trailing edge

This paper describes a direct numerical simulation (DNS) study of turbulent flow over a rectangular trailing edge at a Reynolds number of 1000, based on the freestream quantities and the trailing edge thickness h; the incomin g boundary layer displacement thickness delta* is approximately equal to h. The time-dependent inflow boundary condition is provided by a separate tur bulent boundary layer simulation which is in good agreement with existing c omputational and experimental data. The turbulent trailing edge flow simula tion is carried out using a parallel multi-block code based on finite diffe rence methods and using a multi-grid Poisson solver. The turbulent flow in the near-wake region of the trailing edge has been studied first for the ef fects of domain size and grid resolution. Then two simulations with a total of 256 x 512 x 64 (similar to 8.4 x 10(6)) and 512 x 1024 x 128 (similar t o 6.7 x 10(7)) grid points in the computational domain are carried out to i nvestigate the key flow features. Visualization of the instantaneous flow f ield is used to investigate the complex fluid dynamics taking place in the near-wake region; of particular importance is the interaction between the l arge-scale spanwise, or Karman, vortices and the small-scale quasi-streamwi se vortices contained within the inflow boundary layer Comparisons of turbu lence statistics including the mean flow quantities are presented, as well as the pressure distributions over the trailing edge. A spectral analysis a pplied to the force coefficient in the wall normal direction shows that the main shedding frequency is characterized by a Strouhal number based on h o f approximately 0.118. Finally, the turbulence kinetic energy budget is ana lysed.