Measurement of separate velocity, pressure, and temperature components in turbulent nitrogen supersonic flows.
Academic Article
Overview
Overview
abstract
A computer model was used to simulate the measurement of fluctuating flow properties using resonant Doppler velocimetry. A narrow linewidth laser excites fluorescence from sodium atoms which are seeded into a nitrogen flow. The sensitivity of the fluorescence to fluctuating flow parameters as a function of laser wavelength is different for each flow parameter. Thus, a scan of the laser wavelength allows separate measurement of the time averaged fluctuations of velocity, temperature and pressure. Computer fits to simulated fluorescence profiles from flows with randomly generated fluctuating parameters are shown to accurately reproduce the mean and standard deviations of each separate parameter. Cross correlations are also extracted, but with less accuracy due largely to truncation error in the computer fitting routine.
