Estimating the Full Pressure Field Immediately Downstream from a Propeller Using Stereoscopic PIV

Salt Lake Community College Westpointe Campus, Salt Lake City, UT

Despite their relative importance in aerodynamic and turbulent flow measurements, pressure data has long been limited to time-mean fields made using tedious and intrusive pitot probe arrays. However, velocity-based measurements, such as particle image velocimetry (PIV), can be combined with the governing flow equations to derive high resolution pressure fields in a non-intrusive way. Using phase-locking and a multi-plane stereo-PIV approach, the pressure fields in the wake of an isolated propeller were measured using this method. The results were compared to data obtained from a traditional pitot probe. It was found that the pressure profile from the PIV approach was within the margin of error for the pitot measurements. Breaking down each term of the Navier-Stokes equations showed that the convection terms are much larger than either the Reynolds stress or the viscous terms, making up 97% of the pressure gradients. The pressure gradients and pressure profiles from the convective terms appeared to affect the entire field. The Reynolds stress terms only had a slight impact near the rotor center and the viscous terms were completely negligible.