A general approch for multiple sensor hot wire probes

A method of calibration of multiple-sensor probes and for interpretation of measurement signals is presented in a systematic way in this paper. The method is based on an extension of Jorgensen’s directional response relationship. The measurements are not affected by deviations of the sensors from nominal construction angles or by interference and positioning imperfections. These errors are automatically balanced during the calibration phase. The use of a statistical approach reduces the random errors when the calibration data set presents a sufficient degree of overdetermination. The technique allows the determination of the influence cone as a function of the accepted uncertainty, by means of a post-processing procedure. The method allows an ad hoc angular calibration resulting in an error reduction when a very small variation in velocity direction is expected. The calibration and measurement procedures are very easy to perform. Finally the accuracy of the method for a three-sensor probes has been evaluated by comparison with acquired data and available nominal values.