Van Driest

Table of Contents

• Properties
• Model equations
• Usage
• Further information

Properties

• Van Driest damping function
• Includes additional limiting
• Applied in the region up to \( y^+ \) of 500

Model equations

The Van Driest damping function is given by:

\[ D = 1 - \exp^\frac{-y^+}{A^+} \]

The final length scale is given by:

\[ \Delta = \min \left( \frac{\kappa y}{C_s} D , \Delta_g \right) \]

where \( \Delta_g \) is a geometric-based delta function such as the cube-root volume delta.

Usage

The model is specified using:

delta           vanDriest;

vanDriestCoeffs
{
    delta           <geometricDelta>;

    // Optional entries
    kappa           0.41;
    Aplus           26;
    Cdelta          0.158;
    calcInterval    1;
}

The model requires the near wall distance \(y\) which can be costly to compute for moving mesh cases. Here, the optional calcInterval entry can be used to reduce the update frequency of the wall distance calculation at the expense of increased modelling errors.

Further information

Source code:

• Foam::LESModels::cubeRootVolDelta

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