Seven-Hole Pressure Probe Calibration Method Utilizing Look-Up Error Tables

A two-step calibration and measurement procedure for seven-hole pressure probes has been developed that allows simple and accurate real-time processing. The method adds an extra step to traditional least-squares calibration schemes such as Gallington’ s method (Gallington, R. W., “ Measurement of Very Large Flow Angles with Non-Nulling Seven Hole Probes,”Proceedings of the 27th International Instrumentation Symposium , Instrumentation Society of America, Triangle Park, NC, 1981, pp. 115 ‐130)involving the interpolation of error look-up tables. A measurement system employing the two-step calibration scheme is described. Measurements are made in pipe and wind-tunnel e ows, and a detailed uncertainty analysis is performed, to demonstrate the accuracy of the new scheme. Independent of the new scheme, the measurements also show some effects of Reynolds number, velocity gradient, and turbulenceon theprobeaccuracy. TheReynoldsnumbereffect was notanticipated and may indicate the need for multiple calibrations in some circumstances.