【摘要】 在湍流局地平衡假设下 ,建立了齐次湍能输运方程封闭模型 (HKE) ,并在平板边界层的两种经典流动中加以检验 ,给出 HKE封闭下的流速、湍流动能和湍流混合系数剖面的形式解。结果表明 ,HKE可以避免在流速剪切为零时的无湍流混合问题 ,其解与 L aufer湍流实验吻合 ,因而HKE模型比混合长理论有更合理的内涵。文中还给出 HKE封闭的浅海动力学模型 ,以湍应力和水位梯度力的平衡为运动的基本受力平衡 ,进行了模型的量阶分析和运动分析 :当阻尼频率和运动频率同量阶时 ,惯性运动不可忽略 ;在潮振荡占优的浅海中 ,对流非线性相对于惯性运动为小量 ;当阻尼频率足够大时 ,科氏力项相对于湍应力也可能为小量。更多还原

【Abstract】 Based on the hypotheses of local turbulent equilibrium, a new turbulent closure model based on the using the Homogeneous K equation(HKE) is developed in this paper. Applying this model to solving the flow between two parallel flat planes with the upper one moving homogeneously and to a symmetrical flow with a constant gradient, the profiles of velocity, turbulent kinetic energy and turbulent viscosity are solved. The result obtained from the symmetrical flow is in agreement with Laufer’s experiment. HKE can be used to close the fluid dynamic. Moreover it can avoid the fatal disadvantage of Mixing Length Hypotheses when solving problems with zero velocity shear. It suggests that HKE is superior to the closure model using Mixing Length Hypotheses. A hydrodynamic modle for coastal seas closed by HKE is proposd. Taking into consideration the nonlinear effect of turbulence, the movements in a coastal sea are analyzed. Turbulence presents a wide field of research in the coastal sea. The basic balance in a coastal sea should be between vertical turbulent diffusion and the water level gradient. When the movement frequency is in the same order as the damping frequency, the inertial effect cannot be ignored. In a coastal sea where tide is the dominant movement, the advective nonlinear term is small relative to the inertial effect. When the damping frequency is large enough the Corilios term can also be ignored relative to turbulent stress. For the kinetic boundary condition at the sea surface, rigid lid hypotheses are fit for circulation but not for the tidal oscillation.更多还原