frictionless fluid wall

Module: fluid

Category: nlconstraint

Type string: "frictionless fluid wall"

Parameters

Name	Description	Default	Units
laugon	laugon	1	[]
tol	tol	0.1	[]
penalty	penalty	1	[]
rhs	rhs	0	[]
minaug	minaug	0	[]
maxaug	maxaug	50	[]

Description

One of the natural boundary conditions for fluid analyses is to enforce zero fluid velocity normal to a boundary, implying that this boundary is a frictionless fluid wall. In some analyses however, this natural boundary condition may not be enforced sufficiently well. In such cases, use this frictionless fluid wall linear constraint to produce a more strict enforcement of this condition.

<constraint type="frictionless fluid wall" name="FrictionlessFluidWall1" surface="FrictionlessFluidWall1">
    <laugon>0</laugon>
    <tol>0.2</tol>
    <penalty>1</penalty>
    <minaug>0</minaug>
    <maxaug>10</maxaug>
</constraint>

In fluid-structure interaction analyses, this constraint may be used in conjunction with the symmetry plane described in symmetry plane, using a lower value of the penalty parameter, as may be necessary in practice.