Nanostructured tracers for laser-based diagnostics in high-speed flows

Nanostructured tracers for laser-based diagnostics in high-speed flows

The potential application of aggregates of nanoparticles for high-speed flow diagnostics is investigated. Aluminum nanoparticles around 10 nm in diameter are produced by spark discharge in argon gas. Through rapid coagulation and oxidation, aggregates of small effective density are formed. They are characterized by microscopy and their aerodynamics and optical properties are theoretically evalu...

Simultaneous High-resolution Optical Wavefront and Flow Diagnostics for High-speed Flows

Narrow-linewidth megahertz-rate pulse-burst laser for high-speed flow diagnostics.

A second-generation pulse-burst laser system for high-speed flow diagnostics is described in detail. The laser can produce a burst of high-energy pulses (of the order of hundreds of millijoules per pulse) with individual pulse durations of less than 10 ns and pulse separations as short as 1 micros. A key improvement is the addition of a phase-conjugate mirror, which effectively isolates the hig...

Study of Parameters Affecting Separation Bubble Size in High Speed Flows using k-ω Turbulence Model

Shock waves generated at different parts of vehicle interact with the boundary layer over the surface at high Mach flows. The adverse pressure gradient across strong shock wave causes the flow to separate and peak loads are generated at separation and reattachment points. The size of separation bubble in the shock boundary layer interaction flows depends on various parameters. Reynolds-averaged...

Cavity Oscillation Mechanisms in High-Speed Flows

An experimental study was conducted to investigate the physics underlying the oscillation cycle of high Mach number, turbulent, open cavity flows. The specific aim was to investigate how the interaction between the cavity acoustics and the shear layer dynamics is affected by increasing Mach number. In the experiments the free-stream Mach numbers tested were 2 and 5, the cavity length-to-depth r...