Measurement of pressure-velocity correlations in turbulent reacting flows

The pressure-velocity correlation has long posed a major obstacle to the modeling of turbulent flows, due to difficulties in measuring fluctuating pressure and velocity simultaneously in a flow field. Measurements in hot reacting flows encountered in propulsion devices require a new approach. Static pressure fluctuations and the pressure-velocity correlation are derived from simultaneous measurements of total pressure, heat transfer and temperature. A microphone Pitot probe was developed and tested for this application. Hot-film and cooled-film anemometer probes were used to measure heat transfer. Coated platinum-rhodium finewire thermocouples were used to measure temperature. Voltage signals from the probes, recorded simultaneously, are analyzed using a Fourier analyzer system. The probe systems are treated as constant parameter linear systems, and statistical time series analysis is employed to get power and cross spectra and the required correlations.