From c7ca458e18aa1d9aee5a700b9309b2c094479c54 Mon Sep 17 00:00:00 2001
From: henry <Henry Weller h.weller@opencfd.co.uk>
Date: Tue, 6 May 2008 11:59:46 +0100
Subject: [PATCH] Added Yi Wang's RMS correction factor and parameter alpha.
---
.../turbulentInlet/turbulentInletFvPatchField.C | 16 +++++++++++++---
.../turbulentInlet/turbulentInletFvPatchField.H | 13 ++++++++++++-
2 files changed, 25 insertions(+), 4 deletions(-)
diff --git a/src/finiteVolume/fields/fvPatchFields/derived/turbulentInlet/turbulentInletFvPatchField.C b/src/finiteVolume/fields/fvPatchFields/derived/turbulentInlet/turbulentInletFvPatchField.C
index e3aa394f352..f56c7f21848 100644
--- a/src/finiteVolume/fields/fvPatchFields/derived/turbulentInlet/turbulentInletFvPatchField.C
+++ b/src/finiteVolume/fields/fvPatchFields/derived/turbulentInlet/turbulentInletFvPatchField.C
@@ -44,6 +44,7 @@ turbulentInletFvPatchField<Type>::turbulentInletFvPatchField
ranGen_(label(0)),
fluctuationScale_(pTraits<Type>::zero),
referenceField_(p.size()),
+ alpha_(0.1),
curTimeIndex_(-1)
{}
@@ -61,6 +62,7 @@ turbulentInletFvPatchField<Type>::turbulentInletFvPatchField
ranGen_(label(0)),
fluctuationScale_(ptf.fluctuationScale_),
referenceField_(ptf.referenceField_, mapper),
+ alpha_(ptf.alpha_),
curTimeIndex_(-1)
{}
@@ -77,6 +79,7 @@ turbulentInletFvPatchField<Type>::turbulentInletFvPatchField
ranGen_(label(0)),
fluctuationScale_(pTraits<Type>(dict.lookup("fluctuationScale"))),
referenceField_("referenceField", dict, p.size()),
+ alpha_(dict.lookupOrDefault<scalar>("alpha", 0.1)),
curTimeIndex_(-1)
{
if (dict.found("value"))
@@ -103,6 +106,7 @@ turbulentInletFvPatchField<Type>::turbulentInletFvPatchField
ranGen_(ptf.ranGen_),
fluctuationScale_(ptf.fluctuationScale_),
referenceField_(ptf.referenceField_),
+ alpha_(ptf.alpha_),
curTimeIndex_(-1)
{}
@@ -118,6 +122,7 @@ turbulentInletFvPatchField<Type>::turbulentInletFvPatchField
ranGen_(ptf.ranGen_),
fluctuationScale_(ptf.fluctuationScale_),
referenceField_(ptf.referenceField_),
+ alpha_(ptf.alpha_),
curTimeIndex_(-1)
{}
@@ -170,9 +175,14 @@ void turbulentInletFvPatchField<Type>::updateCoeffs()
ranGen_.randomise(randomField[facei]);
}
- patchField =
- 0.9*patchField
- + 0.1*
+ // Correction-factor proposed by Yi Wang to compensate for the loss
+ // of RMS fluctuation due to the temporal correlation introduced by
+ // the alpha parameter.
+ scalar rmsCorr = sqrt(12*(2*alpha_ - sqr(alpha_)))/alpha_;
+
+ patchField =
+ (rmsCorr*(1 - alpha_))*patchField
+ + (rmsCorr*alpha_)*
(
referenceField_
+ cmptMultiply
diff --git a/src/finiteVolume/fields/fvPatchFields/derived/turbulentInlet/turbulentInletFvPatchField.H b/src/finiteVolume/fields/fvPatchFields/derived/turbulentInlet/turbulentInletFvPatchField.H
index 9e2fbfdf1f1..00e05fd58b5 100644
--- a/src/finiteVolume/fields/fvPatchFields/derived/turbulentInlet/turbulentInletFvPatchField.H
+++ b/src/finiteVolume/fields/fvPatchFields/derived/turbulentInlet/turbulentInletFvPatchField.H
@@ -26,7 +26,17 @@ Class
Foam::turbulentInletFvPatchField
Description
- Foam::turbulentInletFvPatchField
+ Generate a fluctuating inlet condition by adding a random component
+ to a reference (mean) field.
+ Input:
+ referenceField
+ Mean field.
+ fluctuationScale
+ RMS fluctuation, provided as the fraction of the mean field.
+ alpha
+ temporal correlation factor;
+ the fraction of the new random component added to the previous
+ time-step (defaults to 0.1).
SourceFiles
turbulentInletFvPatchField.C
@@ -59,6 +69,7 @@ class turbulentInletFvPatchField
Random ranGen_;
Type fluctuationScale_;
Field<Type> referenceField_;
+ scalar alpha_;
label curTimeIndex_;
--
GitLab