We give an alternative proof for a classical result (due to Longuet-Higgins) that provides an estimate for the decay rate with depth of the velocity beneath two-dimensional, spatially periodic, irrotational water waves over a flat bed. Furthermore, an improvement to the same estimate is presented.

中文翻译：

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无旋周期性水波中速度随深度的减小

我们为经典结果（由于 Longuet-Higgins）提供了另一种证明，该结果提供了对平面上二维、空间周期性、无旋水波下方速度深度的衰减率的估计。此外，还提出了对相同估计的改进。