#include #include "meshing.hpp" namespace netgen { void InsertVirtualBoundaryLayer (Mesh & mesh) { cout << "Insert virt. b.l." << endl; int surfid; cout << "Boundary Nr:"; cin >> surfid; int i; int np = mesh.GetNP(); cout << "Old NP: " << mesh.GetNP() << endl; cout << "Trigs: " << mesh.GetNSE() << endl; NgBitArray bndnodes(np); NgArray mapto(np); bndnodes.Clear(); for (i = 1; i <= mesh.GetNSeg(); i++) { int snr = mesh.LineSegment(i).edgenr; cout << "snr = " << snr << endl; if (snr == surfid) { bndnodes.Set (mesh.LineSegment(i)[0]); bndnodes.Set (mesh.LineSegment(i)[1]); } } for (i = 1; i <= mesh.GetNSeg(); i++) { int snr = mesh.LineSegment(i).edgenr; if (snr != surfid) { bndnodes.Clear (mesh.LineSegment(i)[0]); bndnodes.Clear (mesh.LineSegment(i)[1]); } } for (i = 1; i <= np; i++) { if (bndnodes.Test(i)) mapto.Elem(i) = mesh.AddPoint (mesh.Point (i)); else mapto.Elem(i) = 0; } for (i = 1; i <= mesh.GetNSE(); i++) { Element2d & el = mesh.SurfaceElement(i); for (int j = 1; j <= el.GetNP(); j++) if (mapto.Get(el.PNum(j))) el.PNum(j) = mapto.Get(el.PNum(j)); } int nq = 0; for (i = 1; i <= mesh.GetNSeg(); i++) { int snr = mesh.LineSegment(i).edgenr; if (snr == surfid) { int p1 = mesh.LineSegment(i)[0]; int p2 = mesh.LineSegment(i)[1]; int p3 = mapto.Get (p1); if (!p3) p3 = p1; int p4 = mapto.Get (p2); if (!p4) p4 = p2; Element2d el(QUAD); el.PNum(1) = p1; el.PNum(2) = p2; el.PNum(3) = p3; el.PNum(4) = p4; el.SetIndex (2); mesh.AddSurfaceElement (el); nq++; } } cout << "New NP: " << mesh.GetNP() << endl; cout << "Quads: " << nq << endl; } /* Philippose Rajan - 11 June 2009 Function to calculate the surface normal at a given vertex of a surface element, with respect to that surface element. This function is used by the boundary layer generation function, in order to calculate the effective direction in which the prismatic layer should grow */ inline Vec<3> GetSurfaceNormal(Mesh & mesh, const Element2d & el) { auto v0 = mesh[el[0]]; auto v1 = mesh[el[1]]; auto v2 = mesh[el[2]]; Vec<3> vec1 = v1-v0; Vec<3> vec2 = v2-v0; Vec<3> normal = Cross(vec1, vec2); normal.Normalize(); return normal; } /* Philippose Rajan - 11 June 2009 modified by Christopher Lackner Apr 2020 Added an initial experimental function for generating prismatic boundary layers on a given set of surfaces. The number of layers, height of the first layer and the growth / shrink factor can be specified by the user Currently, the layer height is calculated using: height = h_first_layer * (growth_factor^(num_layers - 1)) */ void GenerateBoundaryLayer (Mesh & mesh, const BoundaryLayerParameters & blp) { PrintMessage(1, "Generating boundary layer..."); PrintMessage(3, "Old NP: ", mesh.GetNP()); PrintMessage(3, "Old NSE: ",mesh.GetNSE()); map, int> domains_to_surf_index; map, int> pi_to_edgenr; map last_layer_surface_index_map; int max_surface_index = mesh.GetNFD(); int max_edge_nr = -1; for(const auto& seg : mesh.LineSegments()) if(seg.edgenr > max_edge_nr) max_edge_nr = seg.edgenr; for(int layer = blp.heights.Size(); layer >= 1; layer--) { PrintMessage(3, "Generating layer: ", layer); auto map_surface_index = [&](auto si) { if(last_layer_surface_index_map.find(si) == last_layer_surface_index_map.end()) { last_layer_surface_index_map[si] = ++max_surface_index; auto& old_fd = mesh.GetFaceDescriptor(si); int domout = blp.outside ? old_fd.DomainOut() : blp.new_matnrs[layer-1]; int domin = blp.outside ? blp.new_matnrs[layer-1] : old_fd.DomainIn(); // -1 surf nr is so that curving does not do anything FaceDescriptor fd(-1, domin, domout, -1); fd.SetBCProperty(max_surface_index); mesh.AddFaceDescriptor(fd); mesh.SetBCName(max_surface_index-1, "mapped_" + old_fd.GetBCName()); return max_surface_index; } return last_layer_surface_index_map[si]; }; mesh.UpdateTopology(); auto& meshtopo = mesh.GetTopology(); auto layerht = blp.heights[layer-1]; PrintMessage(5, "Layer Height = ", layerht); // Need to store the old number of points and // surface elements because there are new points and // surface elements being added during the process int np = mesh.GetNP(); int nse = mesh.GetNSE(); int ne = mesh.GetNE(); // Safety measure to ensure no issues with mesh // consistency int nseg = mesh.GetNSeg(); // Indicate which points need to be remapped BitArray bndnodes(np+1); // big enough for 1-based array // Map of the old points to the new points Array mapto(np); // Growth vectors for the prismatic layer based on // the effective surface normal at a given point Array, PointIndex> growthvectors(np); growthvectors = 0.; // Bit array to identify all the points belonging // to the surface of interest bndnodes.Clear(); // Run through all the surface elements and mark the points // belonging to those where a boundary layer has to be created. // In addition, also calculate the effective surface normal // vectors at each of those points to determine the mesh motion // direction PrintMessage(3, "Marking points for remapping..."); for(const auto& sel : mesh.SurfaceElements()) if (blp.surfid.Contains(sel.GetIndex())) { auto n2 = GetSurfaceNormal(mesh,sel); if(!blp.outside) n2 *= -1; for(auto pi : sel.PNums()) { // Set the bitarray to indicate that the // point is part of the required set bndnodes.SetBit(pi); // Add the surface normal to the already existent one // (This gives the effective normal direction at corners // and curved areas) 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); } } // project growthvector on surface for inner angles // for(const auto& sel : mesh.SurfaceElements()) // if(!blp.surfid.Contains(sel.GetIndex())) // { // auto n = GetSurfaceNormal(mesh, sel); // for(auto pi : sel.PNums()) // { // if(growthvectors[pi].Length2() == 0.) // continue; // auto& g = growthvectors[pi]; // auto ng = n * g; // auto gg = g * g; // auto nn = n * n; // if(fabs(ng*ng-nn*gg) < 1e-12 || fabs(ng) < 1e-12) continue; // auto a = -ng*ng/(ng*ng-nn * gg); // auto b = ng*gg/(ng*ng-nn*gg); // g += a*g + b*n; // } // } if (!blp.grow_edges) { for(const auto& sel : mesh.LineSegments()) { int count = 0; for(const auto& sel2 : mesh.LineSegments()) if(((sel[0] == sel2[0] && sel[1] == sel2[1]) || (sel[0] == sel2[1] && sel[1] == sel2[0])) && blp.surfid.Contains(sel2.si)) count++; if(count == 1) { bndnodes.Clear(sel[0]); bndnodes.Clear(sel[1]); } } } // Add additional points into the mesh structure in order to // clone the surface elements. // Also invert the growth vectors so that they point inwards, // and normalize them PrintMessage(3, "Cloning points and calculating growth vectors..."); for (PointIndex pi = 1; pi <= np; pi++) { if (bndnodes.Test(pi)) mapto[pi] = mesh.AddPoint(mesh[pi]); else mapto[pi].Invalidate(); } // Add quad surface elements at edges for surfaces which // don't have boundary layers // Bit array to keep track of segments already processed BitArray segsel(nseg); // Set them all to "1" to initially activate all segments segsel.Set(); // remove double segments (if more than 2 surfaces come together // in one edge. If one of them is mapped, keep that one and // map the others to it. Array> segmap(nseg); for(SegmentIndex sei = 0; sei < nseg; sei++) { if(!segsel.Test(sei)) continue; const auto& segi = mesh[sei]; for(SegmentIndex sej = 0; sej < nseg; sej++) { if(sej == sei || !segsel.Test(sej)) continue; const auto& segj = mesh[sej]; if(segi[0] == segj[0] && segi[1] == segj[1]) { SegmentIndex main, other; if(blp.surfid.Contains(segi.si)) { main = sei; other = sej; } else { main = sej; other = sei; } segsel.Clear(other); for(auto& s : segmap[other]) segmap[main].Append(s); segmap[other].SetSize(0); segmap[main].Append(other); if(other == sei) sej = nseg; } } } PrintMessage(3, "Adding 2D Quad elements on required surfaces..."); if(blp.grow_edges) for(SegmentIndex sei = 0; sei < nseg; sei++) { // Only go in if the segment is still active, and if both its // surface index is part of the "hit-list" if(segsel.Test(sei)) { // copy here since we will add segments and this would // invalidate a reference! auto segi = mesh[sei]; if(blp.surfid.Contains(segi.si)) { // clear the bit to indicate that this segment has been processed segsel.Clear(sei); // Find matching segment pair on other surface for(SegmentIndex sej = 0; sej < nseg; sej++) { // copy here since we will add segments and this would // invalidate a reference! auto segj = mesh[sej]; // Find the segment pair on the neighbouring surface element // Identified by: seg1[0] = seg_pair[1] and seg1[1] = seg_pair[0] if(segsel.Test(sej) && ((segi[0] == segj[1]) && (segi[1] == segj[0]))) { // clear bit to indicate that processing of this segment is done segsel.Clear(sej); // if segj is not in surfel list we nned to add quads if(!blp.surfid.Contains(segj.si)) { SurfaceElementIndex pnt_commelem; SetInvalid(pnt_commelem); auto pnt1_elems = meshtopo.GetVertexSurfaceElements(segj[0]); auto pnt2_elems = meshtopo.GetVertexSurfaceElements(segj[1]); for(auto pnt1_sei : pnt1_elems) if(mesh[pnt1_sei].GetIndex() == segj.si) for(auto pnt2_sei : pnt2_elems) if(pnt1_sei == pnt2_sei) pnt_commelem = pnt1_sei; if(IsInvalid(pnt_commelem)) throw Exception("Couldn't find element on other side for " + ToString(segj[0]) + " to " + ToString(segj[1])); const auto& commsel = mesh[pnt_commelem]; Element2d sel(QUAD); auto seg_p1 = segi[0]; auto seg_p2 = segi[1]; if(blp.outside) Swap(seg_p1, seg_p2); sel[0] = seg_p1; sel[1] = seg_p2; sel[2] = mapto[seg_p2]; sel[3] = mapto[seg_p1]; auto domains = make_tuple(commsel.GetIndex(), blp.new_matnrs[layer-1], mesh.GetFaceDescriptor(commsel.GetIndex()).DomainOut()); if(domains_to_surf_index.find(domains) == domains_to_surf_index.end()) { domains_to_surf_index[domains] = ++max_surface_index; domains_to_surf_index[make_tuple(max_surface_index, get<1>(domains), get<2>(domains))] = max_surface_index; FaceDescriptor fd(-1, get<1>(domains), get<2>(domains), -1); fd.SetBCProperty(max_surface_index); mesh.AddFaceDescriptor(fd); mesh.SetBCName(max_surface_index-1, mesh.GetBCName(get<0>(domains)-1)); } auto new_index = domains_to_surf_index[domains]; sel.SetIndex(new_index); mesh.AddSurfaceElement(sel); // Add segments Segment seg_1, seg_2; seg_1[0] = mapto[seg_p1]; seg_1[1] = seg_p1; seg_2[0] = seg_p2; seg_2[1] = mapto[seg_p2]; auto points = make_tuple(seg_p1, mapto[seg_p1]); if(pi_to_edgenr.find(points) == pi_to_edgenr.end()) pi_to_edgenr[points] = ++max_edge_nr; seg_1.edgenr = pi_to_edgenr[points]; seg_1[2] = PointIndex::INVALID; seg_1.si = new_index; mesh.AddSegment(seg_1); points = make_tuple(seg_p2, mapto[seg_p2]); if(pi_to_edgenr.find(points) == pi_to_edgenr.end()) pi_to_edgenr[points] = ++max_edge_nr; seg_2[2] = PointIndex::INVALID; seg_2.edgenr = pi_to_edgenr[points]; seg_2.si = new_index; mesh.AddSegment(seg_2); } // in last layer insert new segments if(layer == blp.heights.Size()) { max_edge_nr++; if(!blp.surfid.Contains(segj.si)) { Segment s3 = segj; s3.si = map_surface_index(segj.si)-1; Swap(s3[0], s3[1]); if(blp.outside) { s3[0] = mapto[s3[0]]; s3[1] = mapto[s3[1]]; } else s3.edgenr = max_edge_nr; mesh.AddSegment(s3); } Segment s1 = segi; Segment s2 = segj; s1.edgenr = max_edge_nr; s2.edgenr = max_edge_nr; auto side_surf = domains_to_surf_index[make_tuple(s2.si, blp.new_matnrs[layer-1], mesh.GetFaceDescriptor(s2.si).DomainOut())]; if(blp.surfid.Contains(segj.si)) s2.si = map_surface_index(segj.si); else { if(blp.outside) { s2.si = side_surf; } else mesh[sej].si = side_surf; } s1.si = map_surface_index(s1.si); s1.surfnr1 = s1.surfnr2 = s2.surfnr1 = s2.surfnr2 = -1; mesh.AddSegment(s1); mesh.AddSegment(s2); } segmap.SetSize(mesh.LineSegments().Size()); for(auto sei2 : segmap[sei]) { auto& s = mesh[sei2]; if(blp.outside && layer == blp.heights.Size()) { if(blp.surfid.Contains(s.si)) s.si = map_surface_index(s.si); s.edgenr = max_edge_nr; } else { s[0] = mapto[s[0]]; s[1] = mapto[s[1]]; } } for(auto sej2 : segmap[sej]) { auto& s = mesh[sej2]; if(blp.outside && layer == blp.heights.Size()) { if(blp.surfid.Contains(s.si)) s.si = map_surface_index(s.si); s.edgenr = max_edge_nr; } else { s[0] = mapto[s[0]]; s[1] = mapto[s[1]]; } } // do not use segi (not even with reference, since // mesh.AddSegment will resize segment array and // invalidate reference), this is why we copy it!!! mesh[sei][0] = mapto[segi[0]]; mesh[sei][1] = mapto[segi[1]]; mesh[sej][0] = mapto[segj[0]]; mesh[sej][1] = mapto[segj[1]]; } } } else { // check if it doesn't contain the other edge as well // and if it doesn't contain both mark them as done and // if necessary map them for(SegmentIndex sej = 0; sej vertices; switch(classify) { case 6: { if(blp.outside) throw Exception("Type 6 quad outside layer is not yet implemented!"); el = Element(PRISM); vertices = {0, 1, 5, 3, 2, 6}; break; } case 9: { if(blp.outside) throw Exception("Type 9 quad outside layer is not yet implemented!"); el = Element(PRISM); vertices = { 1, 4, 0, 2, 7, 3 }; break; } case 15: { vertices = { 0, 1, 2, 3, 4, 5, 6, 7 }; if(!blp.outside) { Swap(vertices[1], vertices[3]); Swap(vertices[5], vertices[7]); } el = Element(HEX); break; } default: throw Exception("Type " + ToString(classify) + " for quad layer not yet implemented!"); } for(auto i : Range(el.PNums())) el.PNums()[i] = nums[vertices[i]]; } el.SetIndex(blp.new_matnrs[layer-1]); mesh.AddVolumeElement(el); } } // Finally switch the point indices of the surface elements // to the newly added ones PrintMessage(3, "Transferring boundary layer surface elements to new vertex references..."); for(SurfaceElementIndex sei : Range(nse)) { auto& sel = mesh[sei]; if(!blp.surfid.Contains(sel.GetIndex())) { const auto& fd = mesh.GetFaceDescriptor(sel.GetIndex()); if(blp.outside && (!blp.domains[fd.DomainIn()] && !blp.domains[fd.DomainOut()])) continue; if(!blp.outside && (blp.domains[fd.DomainIn()] || blp.domains[fd.DomainOut()])) continue; } for(auto& pnum : sel.PNums()) if(mapto[pnum].IsValid()) pnum = mapto[pnum]; } for(ElementIndex ei : Range(ne)) { auto& el = mesh[ei]; // only move the elements on the correct side if(blp.outside ? blp.domains[el.GetIndex()] : !blp.domains[el.GetIndex()]) for(auto& pnum : el.PNums()) if(mapto[pnum].IsValid()) pnum = mapto[pnum]; } // Lock all the prism points so that the rest of the mesh can be // optimised without invalidating the entire mesh // for (PointIndex pi = mesh.Points().Begin(); pi < mesh.Points().End(); pi++) for (PointIndex pi = 1; pi <= np; pi++) if(bndnodes.Test(pi)) mesh.AddLockedPoint(pi); // Now, actually pull back the old surface points to create // the actual boundary layers PrintMessage(3, "Moving and optimising boundary layer points..."); for (PointIndex i = 1; i <= np; i++) { if(bndnodes.Test(i)) { MeshPoint pointtomove; pointtomove = mesh.Point(i); mesh.Point(i).SetPoint(pointtomove + layerht * growthvectors[i]); } } mesh.Compress(); } for(int i=1; i <= mesh.GetNFD(); i++) { auto& fd = mesh.GetFaceDescriptor(i); if(blp.surfid.Contains(fd.BCProperty())) { if(blp.outside) fd.SetDomainOut(blp.new_matnrs[blp.new_matnrs.Size()-1]); else fd.SetDomainIn(blp.new_matnrs[blp.new_matnrs.Size()-1]); } } PrintMessage(3, "New NP: ", mesh.GetNP()); PrintMessage(1, "Boundary Layer Generation....Done!"); } }