The omni-directional sensitivity pattern of an integrated, three-dimensional acoustic sensor consisting of four hot-wire particle velocity sensors is analyzed theoretically and experimentally. The influence of the probe surface on the measured direction of particle velocity is nvestigated and a description of the gas flow profile around the integrated sensor is presented. A theoretical model describing the fluid flow in the vicinity of a simplified geometry, a plate of finite width, is shown to give a relatively adequate description for the gas flow around the probe. The analysis results in a number of design rules to optimize the device performance.
van Honschoten, J. W., Yntema, D. R., Wiegerink, R. J., & Elwenspoek, M. C. (2007). Analysis of a three-dimensional particle velocity sensor for design optimization. Journal of micromechanics and microengineering, 17(WP07-01), S137-S146. [10.1088/0960-1317/17/7/S11]. https://doi.org/10.1088/0960-1317/17/7/S11