Three-dimensional traveling waves in a square duct.

ABSTRACT

A nonlinear streamwise traveling-wave solution is obtained by homotopy for square duct flow. For a particular symmetry of the perturbations, this wave comes into existence at about Re(b)=600 (based on half-duct width and bulk speed) for a streamwise wave number alpha=0.85 . The resulting four-vortex mean flow resembles the transitional flow structures observed in previous simulations.