Surface Pressure Measurement on Free-flight Cylinder using Motion-capturing PSP method

Most traditional pressure measurement techniques rely on connecting wires or onboard systems to record pressure. These requirements limit the ability of traditional techniques to measure in-flight objects. This study proposes using two-color pressure-sensitive paint (PSP) to measure the pressure distribution of a model exposed to a shockwave. PSP was chosen over traditional techniques because a wired connection may affect flight dynamics, and an onboard pressure transducer may affect weight distribution. Additionally, the two-color PSP allowed for consistent pressure measurement despite the motion of the model. An unsecured 10 mm diameter cylinder was coated in PSP and placed into a blast tube. The model was then exposed to a shockwave, and the subsequent flow and the results were recorded using a high-speed color camera. A traditional diaphragm pressure transducer was located in the wall of the blast tube for comparison. The pressure increase due to shockwave compression measured by the PSP was within 5% of the increase measured by the in-wall transducer, which resulted in a 3% difference in estimated shockwave speed. The PSP measured a high-pressure region at the leading edge and a dynamic pressure distribution across the model when exposed to post-shockwave flow.