The Visualization of Pressure Distribution along a Plate by Jet Impingement with a Holographic Method

Abstract

A holographic visualization of the pressure on a plate impinged by an axisymmetric turbulent air jet has been carried out. A subdivided silicon rubber sheet located on the plate was transformed with a pressure of the impinging jet and its displacement was measured by the holographic interferometer. The deformation of the rubber plate has no effect on the flow field because of the small wall displacement of order on the 10^-5 m. Fringe patterns of the interferometry correspond to the instantaneous isobaric lines, which correlate well to the ones measured with a semiconducter pressure transducer. On the other hand, when the plate image deformed by an impinging jet is used as the original image, fringe patterns indicate pressure fluctuations. These pressure fluctuation patterns were converted to electric signals by a ccd-camera and microcomputer, and analyzed by a digital image processing method. The flow characteristics of the impinging jet were clarified by this visualization method.