Properties of the reflection coefficient of an elastic layer with asymmetrical fluid loading

In this article the behavior of the plane-wave reflection coefficient of an isotropic elastic layer loaded with different fluids on opposite sides is investigated. For this case an analytical expression is given in a highly physical form. Computation of the fundamental mode zeroes and poles show how total transmission spectra are modified if the density or the sound velocity of only one of the fluids changes, while the corresponding parameter of the other remains constant. This case is of considerable interest when Lamb waves are employed for liquid sensing.