Pneumatic probes such as five-hole probes (5HP) can conveniently measure three-dimensional flow angles, plus total and static pressure. In most applications, transducers are connected using pneumatic tubes, allowing the probe head to be highly miniaturized and robust. However, such “steady” probes are often used in unsteady flows, where they measure a pneumatically averaged flowfield that can differ from the time mean. To better understand these pneumatic averaging effects, an analytical framework is constructed using a quasi-steady model. Total and static pressure coefficients have a symmetric response to both positive and negative incidence. When incidence fluctuates, there is therefore a bias in the pneumatic average. These errors are evident in a shedding wake experiment, where a 5HP overestimates total pressure loss by up to 44% compared to a Kiel probe. These effects can be predicted by coupling an unsteady Reynolds-averaged Navier–Stokes calculation with the quasi-steady model. By predicting pneumatic averaging errors, the quasi-steady model can be used to obtain like-for-like validation of calculations against experimental data. Measurement data can also be corrected, provided that flow angle fluctuations can be measured or estimated. This approach can be readily used to postcorrect the large body of historical data likely to have been corrupted by pneumatic-averaging errors.
Pneumatic-Probe Measurement Errors Caused by Fluctuating Flow Angles
AIAA Journal ; 61 , 7 ; 2922-2931
2023-05-18
10 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
Measurement of Fluctuating Sound in Pneumatic System
British Library Online Contents | 1997
|Pneumatic vortical flow control at high angles of attack
AIAA | 1990
|One-dimensional flow-adaptive measurement grid algorithm for pneumatic probe measurements
Online Contents | 2016
|Fluctuating forces caused by internal two-phase flow on bends and tees
Online Contents | 2006
|