School of Engineering, The University of Queensland
Abstract
Recent investigations have identified a variety of instability modes which may develop to enhance dispersion of co- and counter-rotating vortex pairs. This has application in the aviation industry, where an aircraft’s trailing vortices pose a significant hazard for other nearby aircraft. Batchelor vortices adopt the radial velocity field of Lamb – Oseen vortices, but with an axial velocity component through the core of the vortex, and are often used to represent vortices within an aircraft wake. Recently, the vortex swirl ratio of the Batchelor vortex pair has been identified as a key parameter which may be used to select the mode of instability which develops. Several modes have recently been identified via linear stability analysis. This study extends these prior investigations by considering the non-linear growth of the three-dimensional instabilities acting to disperse the vortex pair. Here, we validate prior linear instability investigations, and compare and contrast the relative ability of several instability modes to achieve improved vortex dispersion. The study has been conducted using a high-order, three-dimensional spectral element method to solve the timedependent incompressible Navier – Stokes equations. The study is conducted at a circulation Reynolds number of 2 800
