High speed flow visualization

A flow visualization system is required to provide multiple imaging of real gas flow structure (shock standoff distance, shock position, boundary layer) about aerodynamic shapes in transient, hypersonic ground test facilities at AEDC. Laser diodes do not provide enough light to overcome the background radiation from real gases. Recent progress and on going research on solid state laser systems, particularly work on alexandrite laser systems, suggest that they are candidates for the required light source. The high pulse energy of these laser sources make discrimination against flow and model radiation possible. The short laser pulses (<50 ns) will enable complex transient effects to be photographed without blurring. The laser will be the light source for standard flow visualization techniques (interferometer, schlieren, shadowgraph). The images will be captured using commercialy available high speed cameras. This Phase I program wil provide the conceptual designs, parametric studies and feasibility calculations and experiments required to design a low risk high speed flow visualization prototype system. In Phase II this prototype system will be checked out on the shock tube driven hypersonic tunnel at Physical Sciences Inc. (PSI) and then tested in a transient hypervelocity facility at AEDC.