Development of Plasma-based Flow Control Techniques for Scramjet Flow Paths

An overview is presented of a comprehensive challenge effort titled "Tip-to-tail Turbulent Scramjet Flowpath Simulation with MHD Energy Bypass". Emphasis is placed on fully three-dimensional (3-D) results obtained at flight conditions. The goal is to employ high-fidelity simulations to lift critical constraints in scramjet development through revolutionary new concepts, which do not readily lend themselves to ground or flight test investigations. The central feature of these techniques is the deployment of 3-D electromagnetic fields to address the harsh airbreathing hypersonic environment. The theoretical model employed resolves the multi-fluid, multi-physics phenomena through a careful blend of first-principles and phenomenological elements chosen to discover new enabling physics. The resulting large and mathematically complex set of equations requires both advanced numerical methods and the massive systems available through the DoD HPC. By coupling results to powerful 3-D visualization techniques, the project has discovered previously unknown effects relating the magnetic, electric and velocity vector fields, as well as location and extent of the ionized region. This has enabled the elucidation of a simple set of principles for effective plasma-based flow control. Key among these are the thermodynamic balance between ponderomotive force and heating through competition between work and Ohmic dissipation and the discriminating effect of energy direction when electrodes are employed. These general observations are employed to develop methods to mitigate heat transfer, separation, mixing and energy management