在柱状多层介质体系下直接场被抵消的证明

The proof of cancelling the direct field under the system of the column-shaped multiply medium

在柱状充流体(或任意内层)的井外为任意多层柱状与井轴共轴的介质体系下,给出点声源在轴线上激发的直接场被井内割线积分抵消的证明。

Under the System of any multiply column-shaped and coaxal medium outside the column-shaped fluid-filled well, the author proves the direct field aroused by the source of the sound on the axis can be cancelled by the integral of the fluid secant in the well.