Propagation of Thermal Waves in Shear Flows

Abstract

New methods of remote control using heat waves have recently attracted considerable interest in defectoscopy. The distinguishing features of these waves are their fast exponential decay and a small phase velocity. The first property falls into the category of drawbacks of the thermal waves when compared with the ultrasound; whereas the second one provides their main advantage (small phase velocities are associated with short wavelengths). Their other advantages for remote control are the transparency of any medium to the heat waves, the convenience of their emission and their reception.