SWAN模型对实验室小尺度浅水波浪模拟研究

基于浅水斜坡地形的物理模型试验数据,考察SWAN模型对实验室小尺度浅水波浪的模拟效果,进而检验其浅水项的模拟精度。模拟中采用直接输入初始测点的实测海浪谱进行造波,重点考察浅水中三波相互作用和变浅破碎两个源项,对不同工况下,SWAN模式在水深条件变化下的有效波高、谱平均周期、海浪谱演化的模拟能力进行研究。研究表明:模拟的有效波高较符合实测波浪的增长和衰减,但谱平均周期计算值明显偏小;海浪谱的能量转移机制同实测有较大区别,频谱模拟结果出现高频高估、低频低估现象。对两个源项进行对比分析得出三波相互作用对海浪谱的能量转换影响远大于变浅破碎耗散。想要提高近岸区谱平均周期和海浪谱的模拟精度则SWAN模型中三波非线性项的计算精确度仍需更多研究和改进。

Application of the SWAN model to shallow water of laboratory scale

Based on the physical model experiment data of shallow water slope terrain, by analyzing the SWAN model of laboratory-scale shallow water wave simulation results, the simulation accuracy of shallow water source terms are verified. As input to SWAN, we use the experimental spectrum at wave gauge 1 as the boundary condition, focusing on the investigation of depth-induced breaking and traid wave-wave interactions. In different conditions, the simulation results of the significant wave heights, the spectral averaged periods and the wave spectrums of the SWAN model are studied. The research shows that the simulated significant wave heights are consistent with the measured wave growth and decay, but the calculated spectral averaged periods are obviously smaller. The energy transfer mechanism of the wave spectrums is quite different from the actual measurements. The spectrum simulation results show high-frequency over-estimation and low-frequency under-estimation. For the two source terms, the traid wave-wave interactions play a more dominant role in the spectral evolution of breaking waves in shallow water. To improve the simulation accuracy of the spectral averaged period and the wave spectrum during the shallow water calculation, it needs more research and improvement of traid wave-wave interactions in the SWAN model.