Study of Three-Dimensional Vortex Shedding in the Wake of a Square Cylinder

207 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1997.It is observed that three-dimensional transition process for square cylinder is similar to that of a circular cylinder. Most notably there is a long wave-length three-dimensional disturbance which becomes unstable at a Reynolds number about 170, followed by the appearance of a short wavelength instability. However, this stability analysis also predicts a intermediate wavenumber disturbance which has a shedding frequency twice that of the base flow. This intermediate wavelength mode has not been observed in analysis of the circular cylinder. The presence of this new intermediate wavelength mode may explain the complicated behavior observed in direct numerical simulations of the non-linear three-dimensional Navier-Stokes equations at low Reynolds numbers.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD