On sound velocities in viscous gas flow with transverse shift

At mathematical simulation of wave processes in a gas tract of energy equipment, e.g. compressors, turbines etc, a question arises: is it correctly to use isentropic value of sound velocity. A formula is obtained for velocity of sound in a viscous gas flow taking into account energy dissipation and heat exchange. Essential dependence of sound velocity in shifted flow from disturbance intensity, frequency, flow speed etc. is found out. It is shown the amplitude of sound velocity changing in shifted flow is inversely proportional to amplitude of density disturbance and grows with flow speed increasing. The results of numerical experiment are presented.