BS in Aerospace Engineering
Aerospace Engineering Department
The calibration and improvement of the Cal Poly supersonic wind tunnel was performed in order to create a fully functional facility for supersonic testing. While investigating possible shocks present in the wind tunnel, it was discovered that the real concern was not the tunnel but the measurement systems. Both measurement systems, pitot tube and Schlieren, were evaluated and were found to be deficient. The pitot system had so much play in it that it bent backward every time the tunnel was run invalidating the results, and giving false shock data. The Schlieren system was missing one vital component to make it work. By definition the Schlieren was not a Schlieren because it was missing a primary light barrier. Furthermore, once the Schlieren component deficiency was corrected, the architecture of the device impeded use with the tunnel because of vibration limitations. The pitot system was corrected by stiffening the holding bracket and also installing a cross bar that limited horizontal movement. Moreover, the inner converging-diverging section was cleaned, smoothed out, and finally aligned and shaped correctly in order to eliminate and lessen probability of shocks. The experiment was also intended to be used as an instructional tool for undergraduate students at Cal Poly. Students will be able to measure a shock using a 15 degree wedge, a pitot measurement system, and the ability to see a shadowgraph of the shock itself.