Computer experiments on the onset of turbulence

We are investigating if small amplitude distributed wall roughness, combined with fluctuations, could nucleate the onset of turbulence in bounded flows. Our direct numerical simulations of turbulent transition isolate the effects of the roughness since the only direct flow perturbations we consider are those due to natural hydrodynamic fluctuations. To properly resolve the range of length scales, we developed a conservative mesh refinement approach for the lattice-Boltzmann method.