Unsteady Flow-Field 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 primarily limited to mean measurements due to the attenuation and lag that is experienced by the pressure signals passing from the ports on the probe tip to the transducers making the pressure measurement. In this work, the capability to reconstruct the unsteady pressure from the pressures measured through the tubing systems has been coupled with a traditional static five-hole probe characterization to allow for unsteady flow-field measurements. Prior to testing, the dynamic response of each pressure port is dynamically characterized via an in-situ technique. Unsteady pressure measurements are then acquired for multiple planes at varying axial distances from the jet exit. Through this approach, it has been determined that the five-hole probe is capable of collecting unsteady measurements that resolve frequencies up to 900 Hz, and provide the statistical quantities of the flow-field that would be expected in an axisymmetric jet. To evaluate the quality of the measurements, the five-hole probe measurements are compared to those using hot-wire anemometry.