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authorAdrian Kummerlaender2019-01-30 16:39:08 +0100
committerAdrian Kummerlaender2019-06-24 15:17:09 +0200
commit860919a818e792185dc902b5be6754c0ff1e2dcb (patch)
treecdf153e710590a9583e4aa30682e829515fce030
parent5aeafca5883f7af387363ede78596ff665b36d0c (diff)
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Refine cylinder2d to stay stable even at very low resolutions
Somewhat fiddled together but works as expected. Refinement areas are informed by Knudsen metric results. The key is to refine the outflow. Sadly this requires refinement-overlap-crossing boundary conditions. Interface for detailed (i.e. cell-relative) grid refinement control still has room for improvement. Mixing physical indicators and cell alignment requirements is problematic.
-rw-r--r--apps/adrian/cylinder2d/cylinder2d.cpp83
1 files changed, 49 insertions, 34 deletions
diff --git a/apps/adrian/cylinder2d/cylinder2d.cpp b/apps/adrian/cylinder2d/cylinder2d.cpp
index ffab6a0..bf25417 100644
--- a/apps/adrian/cylinder2d/cylinder2d.cpp
+++ b/apps/adrian/cylinder2d/cylinder2d.cpp
@@ -39,11 +39,11 @@ typedef double T;
/// Setup geometry relative to cylinder diameter as defined by [SchaeferTurek96]
const T cylinderD = 1.0;
-const int N = 20; // resolution of the model
+const int N = 5; // resolution of the model
const T lx = 22 * cylinderD; // length of the channel
const T ly = 4.1 * cylinderD; // height of the channel
const T Re = 100.; // Reynolds number
-const T uLat = 0.1; // lattice velocity
+const T uLat = 0.05; // lattice velocity
const T maxPhysT = 60.; // max. simulation time in s, SI unit
@@ -67,13 +67,13 @@ void prepareGeometry(Grid2D<T,DESCRIPTOR>& grid)
IndicatorCuboid2D<T> lowerWall(wallExtend, wallOrigin);
sGeometry.rename(1,2,lowerWall);
- IndicatorCuboid2D<T> upperWall(wallExtend, wallOrigin + Vector<T,2> {0,ly});
+ IndicatorCuboid2D<T> upperWall(wallExtend, wallOrigin + Vector<T,2> {0,ly-physSpacing/2});
sGeometry.rename(1,2,upperWall);
}
// Set material number for inflow and outflow
{
- const Vector<T,2> extend { physSpacing/2, ly};
+ const Vector<T,2> extend { physSpacing/2, ly-physSpacing/2};
const Vector<T,2> origin {-physSpacing/4, -physSpacing/4};
IndicatorCuboid2D<T> inflow(extend, origin);
@@ -216,27 +216,58 @@ int main(int argc, char* argv[])
coarseGrid.getConverter().getLatticeRelaxationFrequency(),
instances::getBulkMomenta<T, DESCRIPTOR>());
- sOnLatticeBoundaryCondition2D<T, DESCRIPTOR> coarseSBoundaryCondition(coarseGrid.getSuperLattice());
- createLocalBoundaryCondition2D<T, DESCRIPTOR>(coarseSBoundaryCondition);
+ sOnLatticeBoundaryCondition2D<T, DESCRIPTOR> coarseBoundaryCondition(coarseGrid.getSuperLattice());
+ createLocalBoundaryCondition2D<T, DESCRIPTOR>(coarseBoundaryCondition);
- const Vector<T,2> fineExtend {16*cylinderD, 3.75*cylinderD};
- const Vector<T,2> fineOrigin {0.75*cylinderD, (ly-fineExtend[1])/2};
+ const auto coarseDeltaX = coarseGrid.getConverter().getPhysDeltaX();
+
+ const Vector<T,2> fineExtend {8*cylinderD, ly-2*coarseDeltaX};
+ const Vector<T,2> fineOrigin {0.75*cylinderD, coarseDeltaX};
auto& fineGrid = coarseGrid.refine(fineOrigin, fineExtend);
prepareGeometry(fineGrid);
+ const Vector<T,2> fineExtendB {10*coarseDeltaX, ly};
+ const Vector<T,2> fineOriginB {lx-10*coarseDeltaX, 0};
+
+ auto& fineOutflowGrid = coarseGrid.refine(fineOriginB, fineExtendB, false);
+ prepareGeometry(fineOutflowGrid);
+
+ {
+ const Vector<T,2> origin = fineOutflowGrid.getOrigin();
+ const Vector<T,2> extend = fineOutflowGrid.getExtend();
+
+ const Vector<T,2> extendY = {0,extend[1]};
+
+ coarseGrid.addFineCoupling(fineOutflowGrid, origin, extendY);
+ coarseGrid.addCoarseCoupling(fineOutflowGrid, origin + Vector<T,2> {coarseDeltaX,0}, extendY);
+
+ IndicatorCuboid2D<T> refined(extend, origin + Vector<T,2> {2*coarseDeltaX,0});
+
+ coarseGrid.getSuperGeometry().rename(1,0,refined);
+ coarseGrid.getSuperGeometry().rename(2,0,refined);
+ coarseGrid.getSuperGeometry().rename(4,0,refined);
+ }
+
disableRefinedArea(coarseGrid, fineGrid);
BGKdynamics<T, DESCRIPTOR> fineBulkDynamics(
fineGrid.getConverter().getLatticeRelaxationFrequency(),
instances::getBulkMomenta<T, DESCRIPTOR>());
- sOnLatticeBoundaryCondition2D<T, DESCRIPTOR> fineSBoundaryCondition(fineGrid.getSuperLattice());
- createLocalBoundaryCondition2D<T, DESCRIPTOR>(fineSBoundaryCondition);
+ sOnLatticeBoundaryCondition2D<T, DESCRIPTOR> fineBoundaryCondition(fineGrid.getSuperLattice());
+ createLocalBoundaryCondition2D<T, DESCRIPTOR>(fineBoundaryCondition);
- prepareLattice(coarseGrid, coarseBulkDynamics, coarseSBoundaryCondition);
+ BGKdynamics<T, DESCRIPTOR> fineOutflowBulkDynamics(
+ fineOutflowGrid.getConverter().getLatticeRelaxationFrequency(),
+ instances::getBulkMomenta<T, DESCRIPTOR>());
+
+ sOnLatticeBoundaryCondition2D<T, DESCRIPTOR> fineOutflowBoundaryCondition(fineOutflowGrid.getSuperLattice());
+ createLocalBoundaryCondition2D<T, DESCRIPTOR>(fineOutflowBoundaryCondition);
+
+ prepareLattice(coarseGrid, coarseBulkDynamics, coarseBoundaryCondition);
- const Vector<T,2> fineExtend2 {11*cylinderD, 3*cylinderD};
+ const Vector<T,2> fineExtend2 {4*cylinderD, 2*cylinderD};
const Vector<T,2> fineOrigin2 {1*cylinderD, 2*cylinderD-fineExtend2[1]/2};
auto& fineGrid2 = fineGrid.refine(fineOrigin2, fineExtend2);
@@ -248,29 +279,13 @@ int main(int argc, char* argv[])
fineGrid2.getConverter().getLatticeRelaxationFrequency(),
instances::getBulkMomenta<T, DESCRIPTOR>());
- sOnLatticeBoundaryCondition2D<T, DESCRIPTOR> fineSBoundaryCondition2(fineGrid2.getSuperLattice());
- createLocalBoundaryCondition2D<T, DESCRIPTOR>(fineSBoundaryCondition2);
-
- prepareLattice(fineGrid, fineBulkDynamics, fineSBoundaryCondition);
-
- const Vector<T,2> fineExtend3 {1.5*cylinderD, 1.5*cylinderD};
- const Vector<T,2> fineOrigin3 {2*cylinderD-fineExtend3[0]/2, 2*cylinderD-fineExtend3[1]/2};
-
- auto& fineGrid3 = fineGrid2.refine(fineOrigin3, fineExtend3);
- prepareGeometry(fineGrid3);
-
- disableRefinedArea(fineGrid2, fineGrid3);
-
- BGKdynamics<T, DESCRIPTOR> fineBulkDynamics3(
- fineGrid3.getConverter().getLatticeRelaxationFrequency(),
- instances::getBulkMomenta<T, DESCRIPTOR>());
-
- sOnLatticeBoundaryCondition2D<T, DESCRIPTOR> fineSBoundaryCondition3(fineGrid3.getSuperLattice());
- createLocalBoundaryCondition2D<T, DESCRIPTOR>(fineSBoundaryCondition3);
+ sOnLatticeBoundaryCondition2D<T, DESCRIPTOR> fineBoundaryCondition2(fineGrid2.getSuperLattice());
+ createLocalBoundaryCondition2D<T, DESCRIPTOR>(fineBoundaryCondition2);
- prepareLattice(fineGrid2, fineBulkDynamics2, fineSBoundaryCondition2);
+ prepareLattice(fineGrid, fineBulkDynamics, fineBoundaryCondition);
+ prepareLattice(fineOutflowGrid, fineOutflowBulkDynamics, fineOutflowBoundaryCondition);
- prepareLattice(fineGrid3, fineBulkDynamics3, fineSBoundaryCondition3);
+ prepareLattice(fineGrid2, fineBulkDynamics2, fineBoundaryCondition2);
clout << "Starting simulation..." << endl;
Timer<T> timer(
@@ -286,8 +301,8 @@ int main(int argc, char* argv[])
getResults("level0_", coarseGrid, iT);
getResults("level1_", fineGrid, iT);
+ getResults("level1_outflow_", fineOutflowGrid, iT);
getResults("level2_", fineGrid2, iT);
- getResults("level3_", fineGrid3, iT);
if (iT%statIter == 0) {
timer.update(iT);