Calculation of the Influence of Adhesive Properties of the Couplant on the Echo Amplitude

For test samples that are modeled by shells of revolution—cylindrical, spherical, and toroidal—arbitrarily located relative to a piezoelectric transducer (PET)—we calculate the parameters determined by the adhesive properties of the couplant (surface tension, contact angle of wetting) and dynamic viscosity. These are the thickness of the couplant layer between the PET and the input surface and the maximum gap between the PET working surface and the curved input surface at which acoustic contact is maintained, as well as their effect on the echo amplitude. A comparison with experimental data is carried out.