On Noise Reduction Procedure for Pressure-Sensitive Paint Measurements in Shock-Induced Unsteady Flows

Pressure-sensitive paint (PSP) methods to obtain surface pressure maps over aerodynamic testing models are being investigated by a number of researchers. While PSP techniques offer potential advantages over conventional tap measurements, they generally suffer from a poor signal to noise ratio of the measurements. One powerful tool to filter out noise from signals is the discrete wavelet transform. In the present work, discrete wavelet transform filter bank processing is applied to a signal obtained from a time-resolved pointwise PSP measurement in a shock-induced unsteady flow. The wavelet transform proves effective in filtering noise from aperiodic, un-steady PSP signals. The present results show the importance selecting the number of decomposition levels for best processing performance.