Unsteady Measurements with a Five-Hole Probe

Multi-hole probes have provided reliable flow-field measurements for many years. However, the use of these probes has been limited to mean measurements due to the attenuation and lag that is experienced by the pressure signals passing from the ports on the probe tips to the transducer making the pressure measurement. To address this, some groups have tried to minimize the distance between the ports and the transducer, but this can cause other issues such as resonance in the tubing system. To address this issue, a novel approach for correcting the measured pressures for distortion has been applied to a five-hole probe. In this approach, each port/tube/tranducer is characterized by applying a known signal to the port and recording the measured pressure at the transducer. These measurements are used to tune a model of the tubing system, which can then be used to correct future measurements. The characterization of the probe is discussed, and its use in a jet flow is presented. Unsteady measurements from multi-hole probes make possible a wide range of measurements such as the pressure-velocity correlation.