| Abstract | The pressure-sensitive paint technique (PSP) is used to measure the model surface pressures in wind tunnel testing. In the NRC 1.5 m blowdown wind tunnel, the testing time is limited between 10 to 100 sec, depending on the mass flow rate and the tunnel geometry (2D or 3D test section). Traditionally, production PSP testing required a stationary model during the image acquisition. In order to optimize the testing time, a novel approach for PSP testing in production wind tunnels has been implemented to acquire PSP data on continuously moving objects. This type of testing (pitch and roll sweeps) is the usual method of testing in the 1.5 m blowdown wind tunnel, when conventional instrumentation is used (balance forces and pressure tap data). The measurement method is based on the single shot lifetime method, using UV-LED excitation pulses and 49 Hz image acquisition with a scientific CMOS (sCMOS) camera. The method was demonstrated on the fins of a generic store, tested at M = 0.6, 0.8 and 1.0, at angles of attack from -10° to 20°, and moving at variable pitch rates of 3°/s, -6°/s and 9°/s. The PSP data on the moving model (pitch sweep mode) was compared to PSP data on steady model (pitch step mode), to determine the maximum acceptable pitch rate. The store model was not instrumented with pressure taps and the PSP data from the pitch sweep test was compared with computational fluid dynamics (CFD) simulations. A single Cp offset from the CFD simulations was used to compensate for the model global temperature changes. |
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