Instability Mode Interaction in a Spatially Developing Plane Wake

摘要

The transition mechanism in a plane wake was investigated by means of numerical simulations of instability mode interaction in a spatially developing wake. The incompressible time-dependent 2-D Navier-Stokes equations were solved using finite difference method in the streamwise (x) direction, pseudospectral Fourier method in y direction, and a third order Runge-Kutta scheme for time advancement. The mean profiles, intensity of u-fluctuations and energy spectra of numerical results agree well with experimental measurements. The numerical results show not only the generation of a pair of alternating vortices in the non-linear region, but also, the gradual distortion of a double row of vortices in the downstream location and the loss of a deterministic structure.