Pekeris波导中简正波的复声强及其应用

在Pekeris波导模型下，关注了简正波的矢量场，讨论了简正波水平复声强和垂直复声强的表述，并分析了其特征.单阶简正波在水平方向是行波，相应的水平复声强仅为有功的；在垂直方向为驻波，相应的垂直复声强仅为无功的.而多阶简正波相互干涉，因此总声场的复声强既有有功分量，也有无功分量，其中只有有功分量参与声能的输运，但无功分量是反映声场信息的重要组成部分.通过对垂直(交互)复声强无功分量和水平交互复声强有功分量的数值分析，对于甚低频率的点源声场，发现当声源深度变化时，上述声场分量的正负号呈有规变化，当接收传感器置 关键词： 目标深度分类 复声强 矢量场 Pekeris波导

Complex acoustic intensity of normal modes in Pekeris waveguide and its application

The vector field of normal modes in Pekeris waveguide is studied，and the expression of horizontal and vertical complex acoustic intensity are proposed，especially their characteristics are analyzed in this paper. For the single order mode，the form in the horizontal direction is traveling wave，the corresponding complex acoustic intensity is active，and the vertical form is standing wave，the corresponding complex acoustic intensity is reactive. But for the multi-order mode，either the horizontal or vertical complex acoustic intensity has both active and reactive component because of the interference between the normal modes. Only the active component can transport energy，but the reactive component also carries important information of sound field. The numerical analysis shows that，for the very low frequency sound field of point source，the sign of the active component of horizontal complex acoustic intensity and the reactive component of vertical complex acoustic intensity changed regularly with the change of the depth of acoustic source，so the target depths can be classified by comparing with a critical depth when the receiving transducer is placed in appropriate depths，especially the active component of horizontal complex acoustic intensity，can be used to tell whether the sound source is near the surface or underwater. Further more，the phase angle of complex acoustic intensity is discussed and its distribution regularities are analyzed.