Turbulence measurements in shock induced flows

Turbulence levels were made in the incident and reflected flows of a shock tube. Measurements were made with a double wire hot wire anemometer. Small disturbance approximations were used to relate voltage fluctuations to mass flux and total temperature fluctuations. Computed velocity and density fluctuations, using a zero pressure fluctuation level assumption, followed mass flux and total temperature fluctuations, respectively. An apparent strong influence of driver diaphragm opening characteristics on turbulence level was noted. At fixed Mach number and flow temperature, turbulence intensities are a function of Reynolds number, pressure difference across the diaphragm, and diaphragm material. Measurements of turbulence amplification across the reflected shock were made. Velocity turbulence amplification levels decreased with Reynolds number. Density and total temperature amplification levels are typically 60 to 80% lower than velocity amplification. Standard hot wire techniques can successfully be applied to measure turbulence levels in shock induced flows.