Sound radiation by a plane localized vortex

Abstract

A classical problem on small scale fluctuations of the Rankine vortex in a compressible gas has been numerically simulated. Euler equations for a compressible gas have been solved by the CABARET method. Simulation results well predict the value of the eigenfrequency of the boundary fluctuations for the azimuthal harmonic n = 2 and almost coincide with the analytic solution. The value of the acoustic instability increment has been quantitatively predicted despite the fact that it is small and it has been revealed at a fluc tuation number higher than 100.

Acoustic properties of biaxial crystal of double lead molybdate Pb2MoO5

“…for the waves propagating along the x 2 axis of double lead molybdate crystal and (11) for the waves propagating along the x 3 axis.…”

“…We calculated them on the basis of the original experi mental data on the phase velocity of ultrasound. These data were obtained by the acousto optic method from the Schaefer-Bergmann diagrams and by the echo pulse method (standard acoustical technique) [10][11][12]. The elasticity coefficients were determined using a computer program for fitting parameters, which is based on solving the Christoffel system of equations for ultrasonic velocities.…”