On exact solutions of nonlinear acoustic equations

Solutions of nonlinear acoustic equations describing propagation of strong sound pulses with account of curvature of wave fronts in multi-dimensional geometry are obtained from simple physical considerations. The form of these solutions suggests ansatz suitable for finding solutions of much more general equations of Khokhlov-Zabolotskaya type. General method is illustrated by an example of nonlinear sound pulse focused in one transverse direction and defocused in the other direction.