Experimental investigation on finite-amplitude standing waves: Ⅱ.saturation of harmonics in standing wave field

In the process of shock formation, it was found that the tendency to saturation exists for harmonics with the increasing of foundamental sound pressure level (L_p1).When L_p1 < 153 dB, the relation between the sound pressure amplitude of m-th harmonic p_m and that of fundamental P₁ is about p_m~p₁^m.When the fundamental changes 1 dB,the m-th harmonic will increase m dB. The fundamental and all its harmonics start their transition toward saturation at about the same time during the increas of excitation.The relation of p_m~p₁^m tends to p_m~p₁. The trend of saturation can be divided into three regions in frequency domain:Ⅰ.linear region; Ⅱ. alteration region, and Ⅲ. shock region. When L_p1 > 160 dB, the shock is formed. These results are useful for further theoretical work.