Titre/Title :
Direct numerical simulations of complex 3D turbulent flows : From finite-size particles to grid turbulence
Contact :
Mickael Bourgoin
Résumé/Abstract :
Direct numerical simulations are becoming a valuable tool for studying high-Reynolds number turbulence. One of the usual
methods consists in representing the velocity field by a finite number of Fourier modes. This allows for very high accuracy
and performance on the largest supercomputer currently available through Fast-Fourier transformations. However, this
procedure is limited to the simple spatial configuration of periodic boundary conditions. This talk presents a new approach
in order to extend the mentioned schemes to complex boundary conditions. The basic idea is to combine a standard Fourier-spectral
representation with a penalty type immersed boundary method. Benchmarks on the drag and lift forces of a fixed solid sphere
in wind tunnel simulations show good agreement with previous numerical and experimental data. First applications of this
method concern turbulent wakes of solid sphere as well as statistics of finite-size particles in highly turbulent flows. Preliminary
results on simulations of grid-turbulence will also be presented.