【作者】 梁超；

【导师】 李绍武；

【作者基本信息】 天津大学 ， 水利工程， 2012， 硕士

【摘要】 外海波浪传播到近岸区域,由于水深变浅,波浪发生浅水变形,波高逐渐增大直至破碎,引起强烈的水流紊动、掺混以及各种近岸流系,并产生诸多工程问题。本文将三维辐射应力项和破波产生的水滚切应力项引入三维浅水方程中,同时在紊动源项中考虑波浪破碎效应以及底摩阻项中考虑波流共存的影响,以FVM-OSHER模型为基础建立三维近岸波生流模型,模拟了底部回流和沿岸流现象,并与实测值进行对比。数值模型计算所得到的结果与实测值基本一致。本文分析了紊动源项中考虑破波效应以及引入水滚切应力项对底部回流的影响,结果表明,考虑破波效应和水滚切应力后,计算得到的流速值与实测值更为接近;探讨了底部糙率对底部回流的影响,并给出建议取值范围。更多还原

【Abstract】 As wave propagates to the shallow water, wave heights will increase due to shoaling. Then wave breaking will occur as the wave steepness is too large, accompanied by strong turbulence and mixing which will induce the nearshore currents and engineering problems.In this paper, a new 3D nearshore wave-induced current model is established on the basis of the FVM-OSHER model and by introducing the 3D radiation stress terms and the shear stress terms induced by surface rollers into the 3D shallow water equation. Turbulence due to wave breaking and wave-current co-existing bottom friction effect are also considered in the model. The undertow and longshore current have been simulated with the new model, and the numerical results agree with the experimental data.The effect of the turbulence production due to wave breaking and the shear stress induced by surface rollers to the vertical profile of the undertow have been analyzed. It is shown that the numerical results are closer to the experimental data after these two terms are introduced to the model. The effect of roughness coefficient has been analyzed and the range of roughness coefficient for the computational case has been suggested.更多还原