Eddy Viscosity in Turbulent Flow

Eddy viscosity is a property of turbulent flow that represents the turbulent transport of momentum. It is defined as the proportionality constant between the shear stress and the rate of strain. The eddy viscosity is a key parameter in many turbulent flow models, and it is an essential factor in the prediction of turbulent flow behavior.

Dependent on Flow

The eddy viscosity is dependent on the flow and is not a constant property of the fluid. It varies with the level of turbulence in the flow, which in turn is influenced by the geometry of the flow, the flow velocity, and other factors. The eddy viscosity is typically higher in regions of high turbulence, such as near walls or in regions of flow separation.

Physical Property of the Fluid

The eddy viscosity is a physical property of the fluid, but it is not a fundamental property like viscosity or density. Rather, it is a derived property that reflects the turbulent transport of momentum in the flow. The eddy viscosity is often expressed in terms of a turbulent kinetic energy model, which relates the energy of the turbulent eddies to the eddy viscosity.

Conclusion

In conclusion, the eddy viscosity for turbulent flow is a physical property of the fluid that is dependent on the flow. It is a key parameter in many turbulent flow models and is essential for predicting the behavior of turbulent flows. The eddy viscosity varies with the level of turbulence in the flow, and it is often expressed in terms of a turbulent kinetic energy model.