Abstract
Recent works by several groups have pushed direct numerical simulations of turbulent channel flows up to Re_γ ? 4000-5000. However, these values of Re_γ are still insufficient to discuss the multiscale characteristics in a logarithmic layer, and it is necessary to achieve a turbulent state with a wide range of scales. Numerical simulations using polynomial expansions in wall-normal direction often encountered a serious problem caused by their ill-conditioned characteristics. We report here that this problem does not occur by using a appropriate spectral expansions and that we realize turbulent flows at Re_γ up to at 12000.
