Achieving acoustic cloak by using compressible background flow

Zhang Ruo-Yang¹, Zhao Qing², Ge Mo-Lin^{1, 2, †,}

Distributions of (a) phase velocity v_p, (b) group velocity v_g, in x = 0 plane, of the sound wave incident from the left side, where the background flow (emanative from the center) corresponds to Eq. (12) with n = 4.