Numerical Simulation Of Vortex Breakdown Via 3 D Euler Equations PDF Download

Vortex aerodynamics has played an important role in the development of high performance aircraft in recent years. Although computer codes which solve the three dimensional Euler equations have been used extensively to study leading-edge vortices, they don't include physical viscosity effects associated with vortex flows. The Euler solvers do, however, contain numerical viscosity. As a result, viscosity effects in the Euler solutions such as vortex core size, vortex burst location, leading edge separation, and vortex rollup often do not agree quantitatively with results of physical experiments. The present work defines models for these physical viscosity effects which can be coupled with an Euler solver to improve modeling of vortex physics. A vortex core model is derived from the steady, incompressible Navier-Stokes equations written in cylindrical coordinates. The core model is coupled with an Euler solver and tested on a variety of delta wings over a range of angles of attack. The resulting surface pressure distributions and vortex burst locations are shown to be much closer than results from Euler codes alone. Theses. (jhd).