Continuous Stochastic Data Acquisition for Improved Calibration of Multi-Hole Pressure Probes in Flow Measurements

A new data acquisition method for calibrating multi-hole pressure probes is being investigated to improve the overall measurement quality of these instruments, when operating in quasi-transitory mode. In particular, when these probes are used to perform sweeping measurements of a flow field by continuously changing their orientation or position. A continuous stochastic acquisition of calibration data has been used to account for transient effects and eliminate bias from a predefined acquisition pattern or mitigate hysteresis effects. Different rate of unsteadiness in the positioning of the probe were investigated in order to understand the limit of this calibration methods as well as the range of unsteadiness at which the measuring instrument could operate. The accuracy of measurements obtained using this calibration method was compared with that of the traditional time-averaged calibration method. The new calibration method was found to be more accurate when multi-hole pressure probes are used by a human operator, or for continuous scanning measurements.