Spectral element stability analysis of vortical flows

Abstract

The scope of the present study is to demonstrate the use of spectral/hp-element methods in understanding the global instability mechanisms of vortex dominated flows. Using a BiGlobal stability analysis, analytically constructed and numerically evaluated base flows have been investigated, with the leading eigenvalues obtained by the Arnoldi algorithm. Subsequently, Direct Numerical Simulation (DNS) was used to investigate the non-linear development of an unstable Batchelor vortex. It was found that a spiral-type instability, if allowed to develop in an axially unconstrained manner, leads to an axial loss of energy and the formation of a stagnation point. © 2006 Springer.