Numerical Investigation of The 2D Vortex Whip

Abstract

The concept of a "vortex whip" refers to an idea to improve the performance of vortex generators in inhibiting boundary layer separation. If fluid separation from the surface of a body can be delayed, it is possible to reduce the drag on the body. To implement a vortex whip, an array of vortices of progressively decreasing strengths is set up, all initially the same distance above a flat surface. The strongest vortex induces the next weaker one toward the surface, and it induces the next weakest one even closer to the surface. If all the vortices originated at the edge of the boundary layer, then they would tend to carry high-momentum fluid toward the surface, thereby inhibiting separation. This thesis reports on numerical investigations into the 2D vortex whip problem. Code was written to calculate the vortex trajectories of an array of three vortices of progressively decreasing strengths under potential flow conditions. Calculating these vortex trajectories will be key to answering deeper and more interesting questions about vortex whip dynamics. The significance of this project and the fundamental physics studied has important implications for controlling drag and airflow separation, with direct applications to improving lift of aircraft and turbine power output. Over 25000 simulations of different configurations of the 2D vortex whip were performed. This intensive study led to several profound discoveries, paving the way for future work into the vortex whip and its applications in fluid mechanics.