中文摘要：

在现在的论文，我们努力完成一张图，它在一个二层的系统为界面的波浪理论界定有效性范围，到在海洋工程满足设计的需要。根据周期、独居的波浪的可得到的答案，我们作为原则建议一个指南以波浪时期 T 识别界面的波浪理论的有效性区域，波浪高度 H ，上面的层厚度 d ₁,和更低的层厚度 d ₂,作为在水表面波浪情形浇深度 d 而不是仅仅一个参数。如果无穷和上面的层的水深度比率 r = d ₁/d ₂ 途径浇密度 ρ ₁ 到零，这里建议的图碰巧是 Le M é haut é为免费表面波浪的阴谋。相反，如果在它的严肃加速 g 被在 σ = 的条件下面在这研究定义的减少的严肃代替，为水表面波浪的图能被用于二层的界面的波浪(ρ ₂− ρ ₁)/ρ₂→ 1.0 并且 r 】 1.0。最后，为在二层的液体的各种各样的界面的波浪理论的有效性范围的几个数字被给并且与表面的结果相比飘动。

英文摘要：

In the present paper, we endeavor to accomplish a diagram, which demarcates the validity ranges for interfacial wave theories in a two-layer system, to meet the needs of design in ocean engineering. On the basis of the available solutions of periodic and solitary waves, we propose a guideline as principle to identify the validity regions of the interfacial wave theories in terms of wave period T, wave height H, upper layer thickness dl, and lower layer thick-ness d2, instead of only one parameter-water depth d as in the water surface wave circumstance. The diagram proposed here happens to be Le Mehaute＇s plot for free surface waves if water depth ratio r= d1/d2 approaches to infinity and the upper layer water density p1 to zero. On the contrary, the diagram for water surface waves can be used for two-layer interfacial waves if gravity acceleration g in it is replaced by the reduced gravity defined in this study under the condition of σ=（P2 - Pl）/P2 → 1.0 and r 〉 1.0. In the end, several figures of the validity ranges for various interfacial wavetheories in the two-layer fluid are given and compared with the results for surface waves.