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

• 来源期刊: 中国物理B（英文版）
• 关键词: circumferential guided wave second-harmonic generation (SHG) enhancement effect of cumula-tive SHG closed propagation feature
• 年，卷（期）: 2020,（2）
• 页码范围: 338-346
• 页数: 9页
• 语种: 英文
• DOI: 10.1088/1674-1056/ab628d

摘要

On the basis of second-order perturbation approximate and modal expansion approach, we investigate the enhance-ment effect of cumulative second-harmonic generation (SHG) of circumferential guided waves (CGWs) in a circular tube, which is inherently induced by the closed propagation feature of CGWs. An appropriate mode pair of primary-and double-frequency CGWs satisfying the phase velocity matching and nonzero energy flux is selected to ensure that the second harmonic generated by primary CGW propagation can accumulate along the circumference. Using a coherent superposi-tion of multi-waves, a model of unidirectional CGW propagation is established for analyzing the enhancement effect of cumulative SHG of primary CGW mode selected. The theoretical analyses and numerical simulations performed directly demonstrate that the second harmonic generated does have a cumulative effect along the circumferential direction and the closed propagation feature of CGWs does enhance the magnitude of cumulative second harmonic generated. Potential applications of the enhancement effect of cumulative SHG of CGWs are considered and discussed. The theoretical analysis and numerical simulation perspective presented here yield an insight previously unavailable into the physical mechanism of the enhancement effect of cumulative SHG by closed propagation feature of CGWs in a circular tube.