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fix growthvector direction

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This commit is contained in:
Christopher Lackner 2020-04-25 11:15:36 +02:00
parent d752ada2bd
commit 97baba04a0
1 changed files with 60 additions and 128 deletions
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94
libsrc/meshing/boundarylayer.cpp
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@ -132,16 +132,6 @@ namespace netgen
*/
void GenerateBoundaryLayer (Mesh & mesh, const BoundaryLayerParameters & blp)
{
// Angle between a surface element and a growth-vector below which
// a prism is project onto that surface as a quad
// (in degrees)
double angleThreshold = 5.0;
// Monitor and print out the number of prism and quad elements
// added to the mesh
int numprisms = 0;
int numquads = 0;
PrintMessage(1, "Generating boundary layer...");
PrintMessage(3, "Old NP: ", mesh.GetNP());
PrintMessage(3, "Old NSE: ",mesh.GetNSE());
@ -205,7 +195,7 @@ namespace netgen
// Growth vectors for the prismatic layer based on
// the effective surface normal at a given point
Array<Vec<3>, PointIndex> growthvectors(np);
Array<Array<Vec<3>>, PointIndex> all_growthvectors(np);
growthvectors = 0.;
// Bit array to identify all the points belonging
// to the surface of interest
@ -221,19 +211,26 @@ namespace netgen
for(const auto& sel : mesh.SurfaceElements())
if (blp.surfid.Contains(sel.GetIndex()))
{
auto normal = GetSurfaceNormal(mesh,sel);
auto n2 = GetSurfaceNormal(mesh,sel);
if(!blp.outside)
normal *= -1;
for(int j : Range(sel.PNums()))
n2 *= -1;
for(auto pi : sel.PNums())
{
// Set the bitarray to indicate that the
// point is part of the required set
bndnodes.SetBit(sel[j]);
bndnodes.SetBit(pi);
// Add the surface normal to the already existent one
// (This gives the effective normal direction at corners
// and curved areas)
all_growthvectors[sel[j]].Append(normal);
auto& n1 = growthvectors[pi];
if(n1.Length() == 0) { n1 = n2; continue; }
auto n1n2 = n1 * n2;
auto n1n1 = n1 * n1;
auto n2n2 = n2 * n2;
if(n2n2 - n1n2*n1n2/n1n1 == 0) { n1 = n2; continue; }
n1 += (n2n2 - n1n2)/(n2n2 - n1n2*n1n2/n1n1) * (n2 - n1n2/n1n1 * n1);
}
}
@ -253,25 +250,9 @@ namespace netgen
for (PointIndex pi = 1; pi <= np; pi++)
{
if (bndnodes.Test(pi))
{
mapto[pi] = mesh.AddPoint(mesh[pi]);
growthvectors[pi] = all_growthvectors[pi][0];
for(int i = 1; i < all_growthvectors[pi].Size(); i++)
{
auto& veci = all_growthvectors[pi][i];
for(auto j : Range(i))
{
auto& vecj = all_growthvectors[pi][j];
veci -= 1./(vecj.Length()+1e-10) * (veci * vecj) * vecj;
}
growthvectors[pi] += veci;
}
}
else
{
mapto[pi].Invalidate();
growthvectors[pi] = {0,0,0};
}
}
// Add quad surface elements at edges for surfaces which
@ -336,19 +317,6 @@ namespace netgen
auto surfelem_vect = GetSurfaceNormal(mesh, commsel);
if(blp.outside)
surfelem_vect *= -1;
double surfangle = Angle(growthvectors[segpair_p1],surfelem_vect);
if((surfangle < (90 + angleThreshold) * 3.141592 / 180.0)
&& (surfangle > (90 - angleThreshold) * 3.141592 / 180.0))
{
// Since the surface is lower than the threshold, change the effective
// prism growth vector to match with the surface vector, so that
// the Quad which is created lies on the original surface
//growthvectors.Elem(segpair_p1) = surfelem_vect;
// Add a quad element to account for the prism volume
// element which is going to be added
Element2d sel(QUAD);
if(blp.outside)
Swap(seg_p1, seg_p2);
@ -374,7 +342,6 @@ namespace netgen
auto new_index = domains_to_surf_index[domains];
sel.SetIndex(new_index);
mesh.AddSurfaceElement(sel);
numquads++;
// Add segments
Segment seg_1, seg_2;
@ -400,39 +367,6 @@ namespace netgen
mesh.AddSegment(seg_2);
mesh[sej].si = new_index;
}
else
{
for(auto pnt1_ei : pnt1_elems)
{
auto& pnt_sel = mesh[pnt1_ei];
if(pnt_sel.GetIndex() == mesh[sej].si)
{
for(auto& pi : pnt_sel.PNums())
{
if(pi == segpair_p1)
pi = mapto[seg_p1];
else if(pi == segpair_p2)
pi = mapto[seg_p2];
}
}
}
for(auto sk : pnt2_elems)
{
auto& pnt_sel = mesh[sk];
if(pnt_sel.GetIndex() == mesh[sej].si)
{
for(auto& p : pnt_sel.PNums())
{
if(p == segpair_p1)
p = mapto[seg_p1];
else if (p == segpair_p2)
p = mapto[seg_p2];
}
}
}
}
}
// in last layer insert new segments
if(layer == blp.heights.Size())
@ -680,8 +614,6 @@ namespace netgen
}
PrintMessage(3, "New NP: ", mesh.GetNP());
PrintMessage(3, "Num of Quads: ", numquads);
PrintMessage(3, "Num of Prisms: ", numprisms);
PrintMessage(1, "Boundary Layer Generation....Done!");
}
}