Fluent湍流模型：增强与限制选项

Curvature Correction for the Spalart-Allmaras and two-Equation Models

One weakness of the eddy-viscosity models is that these models are insensitive to streamline curvature and system rotations, which play an important role in many turbulent flow applications. To sensitize the standard eddy-viscosity models to these curvature effects, you can use a modified turbulence production term. For more information, see Curvature Correction for the Spalart-Allmaras and two-Equation Models in the Fluent Theory Guide.

翻译：涡流粘度模型的一个缺点是，这些模型对流线曲率和系统旋转不敏感，而流线曲率和系统旋转在许多湍流应用中起着重要作用。要使标准涡流粘度模型对这些曲率效应敏感，可以使用修改后的湍流产生项。有关更多信息，请参见《Fluent理论指南》中Spalart Allmaras和两个方程模型的曲率校正。

Corner Flow Correction

Eddy-viscosity models have a tendency to over-predict corner flow separation zones. A simplified quadratic non-linear algebraic extension for the Spalart-Allmaras and two-equation models based on the transport equation of the specific dissipation rate ω has been implemented that drives momentum into the corner and can thus reduce corner separation effects. For more information, see Corner Flow Correction in the Fluent Theory Guide.

翻译：涡流粘度模型有过度预测角流分离区的趋势。基于比耗散率ω的输运方程，对Spalart-Allmaras和两个方程模型进行了简化的二次非线性代数扩展，将动量引入角点，从而减少角点分离效应。有关更多信息，请参见《Fluent理论指南》中的“拐角流校正”。

Production Limiters for two-Equation Models

A disadvantage of standard two-equation turbulence models is the excessive generation of the turbulence energy, Gk, in the vicinity of stagnation points. In order to avoid the buildup of turbulent kinetic energy in the stagnation regions, the production term in the turbulence equations can be limited by one of the two formulations described in Production Limiters for two-Equation Models in the Fluent Theory Guide.

翻译：标准双方程湍流模型的一个缺点是在驻点附近过度产生湍流能量Gk。为了避免在停滞区积聚湍流动能，湍流方程中的生成项可以通过《Fluent理论指南》中两个方程模型的生成限制器中描述的两个公式之一进行限制。

Compressibility Effects

when enabled, can improve the prediction of free shear layers at high Mach numbers. This is available when the compressible form of the ideal gas law or the real-gas model is activated for k-epsilon, k-omega, Transition k-kl-omega, Reynolds Stress, Scale-Adaptive Simulation, and Detached Eddy Simulation with the Realizable k-epsilon model. For details, see Model Enhancements.

翻译：启用后，可以改进高马赫数下自由剪切层的预测。当k-epsilon、k-omega、过渡k-kl-omega、雷诺应力、尺度自适应模拟和分离涡模拟的理想气体定律或真实气体模型的可压缩形式被激活时，这是可用的。有关详细信息，请参见模型增强。

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