缓坡地形上内孤立波的破碎及能量分析

Breaking and energy analysis of internal solitary wave over a gentle slope

在大型重力式分层流水槽中对内孤立波沿缓坡地形的演化特征进行了实验研究,利用分层染色标识方法和多点组合探头阵列技术对其传播特性做了定性分析和定量测量。实验表明:下凹型内孤立波沿缓坡地形传播过程中的破碎先从波背部发生,继而演化出上凸型内孤立波;内孤立波破碎不仅与入射波波幅相关,而且受到地形坡度的强烈影响;入射波幅参数??0.4是内孤立波不稳定及破碎的实验判据,内孤立波能量损失出现跃升是其发生破碎的重要特征。研究进一步获得了内孤立波沿缓坡地形的三维演化结构、破碎发生条件和能量变化特性,对于复杂海洋环境中非线性内波传播特性认识及其动力学建模具有重要的科学意义。

The experimental investigation on the propagating and breaking of the internal solitary waves over a gentle slope was conducted in a largely gravitational stratified fluid tank. The qualitative analysis on the evolving characteristics of the internal solitary waves was accomplished by using the dye-tracing technique and the quantitative measurement was carried out by using the multi-channel conductivity-probe arrays. Three-dimensional evolving structure of the internal solitary waves of depression, breaking condition and the characteristics of waves’ energy transformation were also obtained. The experimental results showed that the waves of depression breaking occured in the back of the wave and from the breaking region the waves of elevation were produced. The breaking of the wave was not only related to the amplitude of the incident wave, but also strongly affected by the grade of slope. The experimental criterion of the instability and breaking isα＆gt;0.4. The severe loss of internal solitary waves’ energy is a symbol of the waves’ breaking.