First cell height calculation
From CFD-Wiki
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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]] | |
Revision as of 22:47, 15 May 2007
| Introduction |
| Mesh classification |
| Structured mesh generation |
| Unstructured mesh generation |
| Special topics |
|
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.
