Post on 17-Feb-2017
Basic Boundary Conditions
in OpenFOAM v2.4
Classification
Steady Time-
varying
Dirichlet
Neumann
Robin Not
Implemented
Periodic
Symmetry
fixedValue uniformFixedValue
fixedGradient uniformFixedGradient
zeroGradient
mixed
cyclic
๐ ๐ = ๐ ๐ ๐ ๐, ๐ก = ๐ ๐, ๐ก
๐๐
๐๐๐ = ๐ ๐
๐๐
๐๐๐, ๐ก = ๐ ๐, ๐ก
๐๐
๐๐๐ = 0
a๐ผ ๐ ๐ ๐
+๐ฝ ๐๐๐
๐๐๐ = โ ๐
cyclicAMI
mixed BC
mixed fixedValue
fixedGradient
=
+ ร
ร w
(1-w)
w
fixedValue
fixedGradient
W = 1
W = 0
mixed
symmetryPlane
symmetryPlane or slip?
๐๐
๐๐๐ = 0
Scalar ๐ Vector ๐
๐ ๐ โ ๐ = 0, ๐๐๐ก
๐๐๐ = ๐
symmetryPlane is used on
a single and perfectly flat boundary
slip can be used on curved boundaries
symmetryPlane slip
๐
mixed BC is a combination of
fixedValue and fixedGradient BCs
A weighting parameter w (0-1) switches between these types
directionMixed BC
For vector fields, directionMixed BC
is a combination of fixedValue and
fixedGradient BCs
A weighting parameter (tensor) controls which direction these BCs are apply to
1
2๐โ ๐ + ๐โ๐ ๐
w
๐3 (Zero matrix)
๐ผ3 (Identity matrix) fixedValue
fixedGradient
fixedGradient
fixedValue
Normal direction
Tangential direction
All directions