Session ME - Turbulence Simulations V.
MIXED session, Tuesday afternoon, November 23
Cascade I, Westin Seattle
A specially preconditioned BCGStab (Biconjugate Gradient) method has been developed for the psudospectral solution of nonseparable elliptic equations such as those arising from the implicit solution of the Stokes component of the Navier Stokes equations in a wavy channel after the application of a non-orthogonal mapping to a rectangular domain. Two different preconditioners have been developed: One using a fast spectral solver for the unperturbed straight channel and the other using a second order finite difference solution to the full problem. Both have been proven successful in obtaining in a computationally efficient manner the pseudospectral solution of a general Helmholtz equation within a wavy-walled channel geometry even in the presence of significant wall wave undulation. This efficient conjugate gradient solver has then been used to perform pseudospectral DNS of a Newtonian turbulent flow in a wavy-walled channel. The influence of the wave amplitude on the structure of the turbulence is going to be discussed.