fixedShearStress

Description

The fixedShearStress is boundary condition that sets a user-defined shear stress constant and uniform across a given patch by using the expression:

$$\tau_0 = -\nu_{eff} \frac{d\u}{dn}$$

where:

Property	Description
$\tau$	Shear stress
$\u$	Velocity
$\nu_{eff}$	Effective viscosity
$n$	Wall normal direction

Usage

The condition requires entries in both the boundary and field files.

Boundary file

<patchName>
{
    type            wall;
    ...
}

Field file

<patchName>
{
    // Mandatory entries
    type            fixedShearStress;

    // Optional entries
    tau             <vector>;

    // Inherited entries
    ...
}

where:

Property	Description	Type	Required	Default
type	Type name: fixedShearStress	word	yes	-
tau	Type name: fixedShearStress	vector	no	Zero

The inherited entries are elaborated in:

• fixedValueFvPatchField.H

Further information

Tutorial:

• atmDownstreamDevelopment

Source code:

• fixedShearStress

API:

• Foam::fixedShearStressFvPatchVectorField

History: Introduced in version 2.2.2