Spectral Analysis of a Vortex Wake Behind a Circular Cylinder in a Channel at Moderate Reynolds Numbers

Abstract

Abstract: Direct numerical simulation is employed to study the complex vortical flow in the wake of a circular cylinder in a rectangular channel at 102. Formation and development of vortices behind bodies are governed by two phenomena: Karman street in the central part of the channel and a pair of spiral peripheral vortices near the channel sidewalls. Both of these phenomena introduce their own disturbances to the flow and can be essential depending on the Reynolds number and geometry of the cross section. Fourier transform yielded spectral density of kinetic energy of velocity fluctuations at fixed sample points in the flow and also revealed the patterns in formation of vortical properties of the wake, including the transition to turbulence and self- oscillations of aerodynamics coefficients of the streamlined body.