%ind_tauW%

turbulent boundary settings for turbulent wall stress

Define the turbulent wall stress algorithm to be applied. The user my set the values directly by a Dirichlet condition, or use classical or pressure dependent variants of computation of $ \tau_W$, see DOCUMATH_NumericalIntegrationOfTurbulence.pdf, chapter 1.5 .

BCON($BCindex$,%ind_tauW%) = ( %TAUW_Classical%, limitationMethodAndFactor , %TAUW_TurbulentLayerThickness%, thicknessValue , OPTIONAL: MomentumThickness ) BCON($BCindex$,%ind_tauW%) = ( %TAUW_PressureDependent%, limitationMethodAndFactor , %TAUW_TurbulentLayerThickness%, thicknessValue , OPTIONAL: MomentumThickness ) BCON($BCindex$,%ind_tauW%) = ( %BND_DIRICH%, tauW_x, tauW_y, tauW_z, limitationMethodAndFactor , %TAUW_TurbulentLayerThickness%, thicknessValue , OPTIONAL: MomentumThickness )

limitationMethodAndFactor: default = 1.2 $ \tau_W < \alpha \frac{\rho H u_{ref}}{ \Delta t }$ -> try to keep the wall stress small enough to avoid velocity changes in the time step bigger than the reference velocity $ \alpha u_{ref}$

number in front of the comma: 0 :: no limitation 1 :: $ u_{ref} = \| \mathbf{v} - \mathbf{v}_p \|$ that is relative speed of the point compared to the wall motion 2 :: $ u_{ref} = \frac{h}{\Delta t}$
number after the comma: $ \alpha$ used for limitation (see above)

thicknessValue: default = value given in WallLayer . OPTIONALLY ( preferred option!!! ), the user shall define the turbulent layer thickness behind the keyword %TAUW_TurbulentLayerThickness% . Again, refer to DOCUMATH_NumericalIntegrationOfTurbulence.pdf, chapter 1.5 . The value of $ y_p$ is defined as $ y_p = \text{thicknessValue} \cdot H$ , that is a partition of the local SMOOTH_LENGTH . The outdated idea to define the turbulent layer thickness in %BND_wall% is still activ, but should not be used anymore. The definition of the preset / default value of layer thickness (see WallLayer ) in common_variable remains in action.

List of members:
%TAUW_Classical%	classical approach for turbulent wall stress
%TAUW_PressureDependent%	pressure dependent approach for turbulent wall stress
%BND_DIRICH%	user provided values for turbulent wall stress