Affiliations: Department of Aerospace Engineering, Tohoku
University, Sendai, Miyagi, 980-8579, Japan | NISSAN Motor Co. Ltd., Atsugi, Kanagawa, 243-0192,
Japan
Abstract: In applying Pressure-Sensitive Paint (PSP) to low-speed flow wind
tunnel testing, it is important to minimize any measurement uncertainties.
There are various error sources such as camera noise, misalignment of images
due to model displacement and temperature distribution over the model. Among
these factors, the effects of temperature distribution change during tests on
pressure measurement accuracies were studied in the present paper. Pressure and
temperature distributions over a simplified car model (1/10 scale Ahmed model)
were measured using PSP and Temperature-Sensitive Paint (TSP). Sequential
images were acquired at the same intervals over the entire test period,
including for the conditions before and after the tunnel run. As a result, it
was found that the measurement error caused by temperature distribution over
the model could be reduced using a single-point temperature measurement. In
addition, by measuring surface temperature distributions on the model using
TSP, it was proved that the most accurate pressure measurement could be made by
rationing the wind-off image acquired immediately after shutting down the
tunnel to the wind-on image acquired immediately before shutting down the
tunnel. Using the present measurement technique, complicated pressure fields
over the Ahmed model were successfully visualized.
