I am simulating the propagation of an acoustic field through elastic media. I have identified a pocket of shear stress which is travelling with a speed very close to that of the longitudinal wave speed in the medium (glass optical fibre). The shear wave speed of glass is considerably lower than the measured velocity.
My silly question is: is there any way a longitudinal wave can have a shear velocity component? I'm guessing not, so the follow up is: what kind of wave could this be? It's not in a plate and is not close to the shear velocity so that rules out Rayleigh, Love, Lamb, etc. Are there any other types of exotic wave that fit this criteria?