First cell height calculation
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- | While performing CFD simulations, it is critical that one capture boundary layer near the wall properly. In order to do that, mesh should be generated in such a manner that it captures boundary layer properly. | + | {{Meshing table of contents}} |
+ | While performing CFD simulations, it is critical that one capture boundary layer near the wall properly. In order to do that, the mesh should be generated in such a manner that it captures boundary layer properly. For turbulent flows, calculation of the [[Dimensionless wall distance (y plus) | Y plus]] value of the first interior node/gridpoint helps in doing that. This dimensionless distance is defined as | ||
+ | |||
+ | :<math>y^+ := \frac{u_* \, y}{\nu}</math> | ||
+ | |||
+ | where <math>u_*</math> is the friction velocity defined as | ||
+ | |||
+ | :<math>u_* := \sqrt{\frac{\tau_w}{\rho}}.</math> | ||
+ | |||
+ | The [[Wall shear stress|wall shear]] <math>\tau_w</math> can probably not be determined until after a simulation has been completed, so it is usually necessary to estimate a value, and then check after a simulation is complete. | ||
==Related pages== | ==Related pages== | ||
* [[Dimensionless wall distance (y plus)]] | * [[Dimensionless wall distance (y plus)]] | ||
- | + | * [[Friction velocity]] | |
- | + | * [[Wall shear stress]] |
Latest revision as of 05:06, 29 November 2011
Introduction |
Mesh classification |
Structured mesh generation |
Unstructured mesh generation |
Special topics |
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While performing CFD simulations, it is critical that one capture boundary layer near the wall properly. In order to do that, the mesh should be generated in such a manner that it captures boundary layer properly. For turbulent flows, calculation of the Y plus value of the first interior node/gridpoint helps in doing that. This dimensionless distance is defined as
where is the friction velocity defined as
The wall shear can probably not be determined until after a simulation has been completed, so it is usually necessary to estimate a value, and then check after a simulation is complete.