Compressible large eddy simulations of wall-bounded turbulent flows
using a semi-implicit numerical scheme for low Mach number aeroacoustics
Large eddy simulations (LES) of low-speed, wall-bounded turbulent flows were
conducted by numerically integrating the compressible Navier-Stokes equations
in a generalized curvilinear coordinate system. An efficient numerical scheme
based on a third-order additive semi-implicit Runge-Kutta method for time
advancement and a sixth-order accurate, compact finite-difference scheme for
spatial discretization were used. The convective terms in the wall-normal
direction were treated implicitly to remove the time-step limitation
associated with the use of fine meshes in the near-wall region for high
Reynolds number viscous flows. The dynamic Smagorinsky subgrid-scale eddy
viscosity model was used to close the filtered equations. Generalized
characteristic-based non-reflecting boundary conditions were used together
with grid stretching and enhanced damping in the exit zone. The accuracy and
efficiency of the numerical scheme was assessed by simple acoustic model
problems and by comparing LES predictions for fully developed turbulent
channel flow and turbulent separated flow in an asymmetric diffuser to
previous direct numerical simulation (DNS) and experimental data, respectively.
LES predictions for both flows were in reasonable agreement with the DNS and
experimental mean velocity and turbulence statistics. The findings suggest
that the numerical approach employed here offers comparable accuracy to
similar recent studies at approximately one-third of the computational cost
and may provide both an accurate and efficient way to conduct computational
aeroacoustics studies for low Mach number, confined turbulent flows. Please
see the following reference for details of this work.
Jungsoo Suh, Steven H. Frankel, Luc Mongeau and Michael W.
Plesniak, "Compressible large eddy simulations of wall-bounded turbulent flows
using a semi-implicit numerical scheme for low Mach number aeroacoustics"
Journal of Computational Physics, Volume 215, Issue 2, 1 July 2006, Pages 526–551
Below please find links to applications using the above semi-implicit scheme.
Prof. Frankel's MAIN PAGE