Kinetic Boltzmann Turbulence Method For Improved Predictions of High Energy Beam Quality

ResearchSouth will develop a software product for predicting the effects of turbulent boundary layers and separated regions for analysis and design of defensive missile systems. The basis of the predictive tool is a breakthrough methodology for turbulent compressible aerodynamic flow computation using a kinetic model with the Boltzmann equation. This is an entirely new and different approach from typical Navier-Stokes methods with turbulence modeling which have difficulty producing accurate results. In our Phase I effort, we will formulate turbulence as a collision model in the Boltzmann equation using turbulent eddies as the distribution function. The collision source term will be evaluated by relaxation from an equilibrium state using a computed turbulent length scale. The solution of this model will be the number density distribution of the turbulent eddies. By taking moments of the Boltzmann solutions - the macroscopic flow field quantities, velocity, density, pressure, temperature, and the turbulent viscosity, and length scales are obtained. We will use existing ResearchSouth software for geometry definition, spatial meshing and equation solution. We will then link the turbulent flow results to relevant BMD design issues, such as nozzle flow, external aerodynamic coefficients, and aero-optics effects relevant to airborne lasers and endo-atmospheric interceptors.