Surface temperature and shear stress measurement using liquid crystals

摘要

Abstract: This paper describes a video digital-imaging technique currently being developed to permit the assessment of surface temperature and shear stress distributions using liquid crystals. The background to liquid crystal research in aerodynamics is given, followed by a description of the experimental apparatus, along with the method of digital analysis of the color components of the liquid crystal traces. Some typical calibrations of the crystals are then presented as well as details of the main aspects that need to be considered when using liquid crystals as a quantitative measurement technique. The use of the technique is then illustrated by taking the simple case of a heated circular jet impinging normally onto a flat plate. !22