From 7d252fa900a323ef2067fe4f20e15dfb65f452d7 Mon Sep 17 00:00:00 2001
From: Kutalmis Bercin <kutalmis.bercin@esi-group.com>
Date: Tue, 17 Dec 2019 13:31:28 +0000
Subject: [PATCH] TUT: update velocityDampingConstraint header (#942)
STYLE: add getOrDefault(); const specifiers to velocityDampingConstraint
---
.../velocityDampingConstraint.C | 8 +--
.../velocityDampingConstraint.H | 58 +++++++++++--------
2 files changed, 38 insertions(+), 28 deletions(-)
diff --git a/src/fvOptions/constraints/derived/velocityDampingConstraint/velocityDampingConstraint.C b/src/fvOptions/constraints/derived/velocityDampingConstraint/velocityDampingConstraint.C
index 9d63bfa7002..a9eeea31b35 100644
--- a/src/fvOptions/constraints/derived/velocityDampingConstraint/velocityDampingConstraint.C
+++ b/src/fvOptions/constraints/derived/velocityDampingConstraint/velocityDampingConstraint.C
@@ -55,7 +55,7 @@ void Foam::fv::velocityDampingConstraint::addDamping(fvMatrix<vector>& eqn)
// Note: we want to add
// deltaU/deltaT
// where deltaT is a local time scale:
- // U/(cbrt of volume)
+ // U/(cbrt of volume)
// Since directly manipulating the diagonal we multiply by volume.
const scalarField& vol = mesh_.V();
@@ -66,10 +66,10 @@ void Foam::fv::velocityDampingConstraint::addDamping(fvMatrix<vector>& eqn)
forAll(U, cellI)
{
- scalar magU = mag(U[cellI]);
+ const scalar magU = mag(U[cellI]);
if (magU > UMax_)
{
- scalar scale = sqr(Foam::cbrt(vol[cellI]));
+ const scalar scale = sqr(Foam::cbrt(vol[cellI]));
diag[cellI] += scale*(magU-UMax_);
@@ -129,7 +129,7 @@ bool Foam::fv::velocityDampingConstraint::read(const dictionary& dict)
if (!coeffs_.readIfPresent("UNames", fieldNames_))
{
fieldNames_.resize(1);
- fieldNames_.first() = coeffs_.lookupOrDefault<word>("U", "U");
+ fieldNames_.first() = coeffs_.getOrDefault<word>("U", "U");
}
applied_.setSize(fieldNames_.size(), false);
diff --git a/src/fvOptions/constraints/derived/velocityDampingConstraint/velocityDampingConstraint.H b/src/fvOptions/constraints/derived/velocityDampingConstraint/velocityDampingConstraint.H
index 83c65f29d82..cbbe294b861 100644
--- a/src/fvOptions/constraints/derived/velocityDampingConstraint/velocityDampingConstraint.H
+++ b/src/fvOptions/constraints/derived/velocityDampingConstraint/velocityDampingConstraint.H
@@ -31,28 +31,38 @@ Group
grpFvOptionsConstraints
Description
- Constraint for velocity to dampen velocity fluctuations in
- steady simulations
-
- In case of velocity exceeding limit applies
- a source sink to remove the excess velocity by adding a term
- that drives the velocity to 0 (note that we cannot use the old
- term velocity since it most likely is already excessive). This
- additional constraint is scaled with (U-UMax)/dt
- where dt is a local time scale (= velocity/cellsize) so it switches off
- if the velocity is below UMax.
-
- Constraint described by:
-
- velocityDampingConstraintCoeffs
- {
- UMax 100;
-
- // Optional: name of velocity field (default: U)
- //U U;
- //UNames (U);
- }
-
+ Constraint on velocity field to dampen velocity fluctuations.
+
+ This constraint is primarily used to dampen velocity fluctuations in
+ the start-up phase of simulations. When the local velocity magnitude
+ exceeds the user-supplied maximum value a sink term is activated in
+ the affected region to lower the velocity to the limiting value.
+
+Usage
+ Example of functionality specification in \c fvOptions:
+ \verbatim
+ velocityDamper
+ {
+ // Mandatory entries
+ type velocityDampingConstraint;
+ UMax 200;
+
+ // Optional entries
+ selectionMode all;
+ UNames (U); // names of given velocity fields
+ U U; // name of given velocity field if
+ //`UNames` is not present (default: U)
+
+ // Optional fvOptions entries
+ active true;
+ }
+ \endverbatim
+
+Note
+ When active, this constraint manipulates the system of equations.
+ Users should ensure that it is not active when the case is converged
+ (steady-state) or during the period of interest (transient) to ensure
+ that its presence does not pollute the results.
SourceFiles
velocityDampingConstraint.C
@@ -82,9 +92,9 @@ class velocityDampingConstraint
protected:
- // Protected data
+ // Protected Data
- //- Maximum velocity
+ //- Maximum velocity magnitude
scalar UMax_;
--
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