RHS VISCOUS word1 word2 word3 [zone_selector] |
RHS VISCOUS {THIN-LAYER | TSL | FULL | FACETANGENT | MODE mode} [zone_selector] |
This keyword allows control of the explicit viscous operator used within each zone.
For structured grids, this keyword turns off the viscous terms in specified coordinate directions. The parameters word1, word2, and word3 are keywords controlling the viscous terms in the ξ-, η-, and ζ-directions, respectively. They may have the following values:
Keyword | Meaning | ||
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VISCOUS | Retain all viscous terms in this direction | ||
INVISCID | Neglect all viscous terms in this direction |
The default setting for structured grids is to use the full viscous terms in each direction, unless the RHS VISCOUS keyword is used to specify something different.
When INVISCID is set for a direction, the scalar implicit operator will be used in that direction (the full block implicit operator is used in viscous directions). This may be overridden using the IMPLICIT keyword.
For unstructured grids, this keyword modifies how the viscous discretization is performed. The various options available are as follows:
Keyword | Meaning | ||||||||||||||||||||||||||||||||||||||||||||||
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FULL | Full viscous term discretization derived from the finite
difference between cell centers and constructing other
components from the average of cell gradients.
Equivalent to MODE -5.
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THIN-LAYER | TSL | Pseudo thin-layer approximation for viscous terms obtained
from the finite difference between cell centers.
Equivalent to MODE 6.
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FACETANGENT | Full viscous term discretization derived from the finite
difference between cell centers and preserving the
component of gradient in the plane of the face from
average of cell gradients.
Appears to be more robust for skewed meshes in viscous
dominated regions.
Equivalent to MODE -9.
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MODE mode | Testing option for alternate discretizations.
Positive values of mode result in an additional correction
associated with the jump in face-center reconstructed values.
Other values correspond to different types of corrections to the
computed face gradient. This option should be used carefully,
as unexpected results can arise based on grid quality.
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The default setting for unstructured grids is to use the THIN-LAYER terms, unless the RHS VISCOUS keyword is used to specify something different.
Last updated 1 Apr 2016