Shear waves in a circular gap structure of piezoelectric crystals with rotating cylinder

The circumferential propagation of shear-axial waves in a circular gap structure of 6mm(4mm)-class symmetry piezoelectric crystals with rotating piezoelectric cylinder are considered. Generally the curvature of gap boundaries leads to attenuation waves due to radiation in environment. It is shown that with excess of gap wave phase velocity to linear velocity of surface of rotating cylinder the stationary propagation of gap waves is possible.