| lixx |
November 14, 2013 22:05 |
Questions regarding mappedVelocityFluxFidedValue boundary condition
Hi Foamers,
I have a question regarding the implementation of mappedVelocityFluxFixedValueFvPatchField::updateCo effs(). The code is listed below:
Code:
162 void Foam::mappedVelocityFluxFixedValueFvPatchField::updateCoeffs()
163 {
164 if (updated())
165 {
166 return;
167 }
168
169 // Since we're inside initEvaluate/evaluate there might be processor
170 // comms underway. Change the tag we use.
171 int oldTag = UPstream::msgType();
172 UPstream::msgType() = oldTag+1;
173
174 // Get the mappedPatchBase
175 const mappedPatchBase& mpp = refCast<const mappedPatchBase>
176 (
177 mappedVelocityFluxFixedValueFvPatchField::patch().patch()
178 );
179 const fvMesh& nbrMesh = refCast<const fvMesh>(mpp.sampleMesh());
180 const word& fieldName = dimensionedInternalField().name();
181 const volVectorField& UField =
182 nbrMesh.lookupObject<volVectorField>(fieldName);
183
184 surfaceScalarField& phiField = const_cast<surfaceScalarField&>
185 (
186 nbrMesh.lookupObject<surfaceScalarField>(phiName_)
187 );
188
189 vectorField newUValues;
190 scalarField newPhiValues;
191
192 switch (mpp.mode())
193 {
194 case mappedPolyPatch::NEARESTFACE:
195 {
196 vectorField allUValues(nbrMesh.nFaces(), vector::zero);
197 scalarField allPhiValues(nbrMesh.nFaces(), 0.0);
198
199 forAll(UField.boundaryField(), patchI)
200 {
201 const fvPatchVectorField& Upf = UField.boundaryField()[patchI];
202 const scalarField& phipf = phiField.boundaryField()[patchI];
203
204 label faceStart = Upf.patch().start();
205
206 forAll(Upf, faceI)
207 {
208 allUValues[faceStart + faceI] = Upf[faceI];
209 allPhiValues[faceStart + faceI] = phipf[faceI];
210 }
211 }
212
213 mpp.distribute(allUValues);
214 newUValues.transfer(allUValues);
215
216 mpp.distribute(allPhiValues);
217 newPhiValues.transfer(allPhiValues);
218
219 break;
220 }
221 case mappedPolyPatch::NEARESTPATCHFACE:
222 case mappedPolyPatch::NEARESTPATCHFACEAMI:
223 {
224 const label nbrPatchID =
225 nbrMesh.boundaryMesh().findPatchID(mpp.samplePatch());
226
227 newUValues = UField.boundaryField()[nbrPatchID];
228 mpp.distribute(newUValues);
229
230 newPhiValues = phiField.boundaryField()[nbrPatchID];
231 mpp.distribute(newPhiValues);
232
233 break;
234 }
235 default:
236 {
237 FatalErrorIn
238 (
239 "mappedVelocityFluxFixedValueFvPatchField::"
240 "updateCoeffs()"
241 ) << "patch can only be used in NEARESTPATCHFACE, "
242 << "NEARESTPATCHFACEAMI or NEARESTFACE mode" << nl
243 << abort(FatalError);
244 }
245 }
246
247 operator==(newUValues);
248 phiField.boundaryField()[patch().index()] == newPhiValues;
249
250 // Restore tag
251 UPstream::msgType() = oldTag;
252
253 fixedValueFvPatchVectorField::updateCoeffs();
254 }
When the sampleMode is set to "nearestFace" (line 194-220), why there is a loop
Code:
199 forAll(UField.boundaryField(), patchI)
200 {
201 const fvPatchVectorField& Upf = UField.boundaryField()[patchI];
and why not just directly pass the U and phi on the sampled patch to *this patch?
And Upf here is the boundary field (U field at boundary patches) rather than the U field of the sampled, internal patch (given by the keyword "offset" in file constant/polyMesh/boundary). But later
Code:
206 forAll(Upf, faceI)
207 {
208 allUValues[faceStart + faceI] = Upf[faceI];
209 allPhiValues[faceStart + faceI] = phipf[faceI];
210 }
the value on the boundary (Upf) is stored in allUValues and passed to *this patch. My question is where the sampled patch comes in? I suspect it is the following lines
Code:
174 // Get the mappedPatchBase
175 const mappedPatchBase& mpp = refCast<const mappedPatchBase>
176 (
177 mappedVelocityFluxFixedValueFvPatchField::patch().patch()
178 );
but after checking the constructor of class mappedPatchBase, I did not see how it is achieved.
Can anybody give me a hint? Sorry if this is a silly question. I am now trying to implement a new boundary condition based on this one, but still have some problems.
When using pisoFoam, this updateCoeffs() will be called three times during each time step. Is this right? If I want to keep a running average of the sampled patch, should I do it during each call or do it only once during one time step? If latter, how can I do it? By comparing curTimeIndex with db().time().timeIndex()? |
