Enhancement effect of cumulative second-harmonic generation by closed propagation feature of circumferential guided waves

Gao Guang-Jian¹, Deng Ming-Xi^{2, †}, Hu Ning², Xiang Yan-Xun^{3, ‡}

Dispersion curves for the fundamental and double frequency CGWs in the given circular tube: (a) phase and (b) group velocities.