Wetting_Speed_Blake_Ls

Syntax: Bc Disting For Momentum [{of} SpeciesName | {in} MaterialPhaseName | {ls} {a | b | c}] {@ | at | for | on | over} Mesh Extent Name [Touching TouchingMeshExtent | Opposing OpposingMeshExtent] = Wetting_Speed_Blake_Ls [Using Data Specification Data Spec Name] [V_W = v_w | G = g | Theta = theta | Width = width | Tau = tau]
Summary: Blake level set wetting speed model for momentum distinguishing condition
Description: The wetting condition is governed by

$\v - \delta(F) v_w \sinh\left( g \left(\cos \theta_s - \cos \theta\right) \right) \t_w + \delta(F) \tau \dot{\v} = 0$

where $\v$ is the fluid velocity and $\t_w$ is the tangent to the wall. The function $\delta(F)$ , where $F$ is the level set distance field, is given by

$\delta(F) = \frac{1}{2} \left( 1 + \cos\frac{\pi F}{\alpha} \right)$

when $|F| < \alpha$ and zero elsewhere. Here, $\alpha$ is the half of the WIDTH parameter. The term involving $\tau$ is a transient relaxation term. By default, $\tau = 0$ .

This distinguishing condition is a function of the static and observed contact angles. The static contact angle $\theta_s$ , supplied by the THETA parameter, is fixed. The observed contact angle $\theta$ is computed from the current state of the solution as illustrated in the following diagram. The important point here is that the contact angle is measured through the negative side of the distance function which is denoted PHASE_A in Aria.