Dear Praveen, The Boundary Layer field was an experiment: the 3D version was not functional and has been removed in recent versions. The 2D version is fairly usable. New implementation of boundary layers are forthcoming. In 3D, I currently advise simply using the Extrude command: it will not create fans, but for simple geometries like yours it should be sufficient.
Here's an example: // create a square lc = 0.3; Point(1) = {0.0,0.0,0.0,lc}; Point(2) = {1,0.0,0.0,lc}; Point(3) = {1,1,0.0,lc}; Point(4) = {0,1,0.0,lc}; Line(1) = {4,3}; Line(2) = {3,2}; Line(3) = {2,1}; Line(4) = {1,4}; Line Loop(1) = {2,3,4,1}; Plane Surface(1) = {1}; // create a cube Extrude {0,0.0,1} { Surface{1}; } // remove the volume Delete { Volume{1}; } // extrude the boundary of the cube inwards by 0.05, with 5 layers of elements Extrude { Surface{26, -1, 13, 17, 21, 25}; Layers{5, 0.05}; } // create the inner volume Surface Loop(159) = {92, 158, 70, 48, 136, 114}; Volume(160) = {159}; General.ExpertMode = 1; // disable warning about mixing Delaunay and extrusion > On 14 Sep 2016, at 10:52, Praveen Kumar <prav...@cctech.co.in> wrote: > > Hi, > > I am trying to generate boundary layers on all the surfaces of a simple > rectangular duct geometry (imported stl). The prism layers are not getting > connected on the edges/corners between each surfaces. > > <BL-issue.JPG> > > > Can someone help me understand what is missing here? Please Note, I am using > 2.11.0 version of gmsh as this is not working at all in the latest version > > -------------------------------------- > Merge "duct.stl"; > CreateTopology; > > ll[] = Line "*"; > l = newl; > For j In {0 : #ll[]-1} > Compound Line(l+j) = ll[j]; > EndFor > > ss[] = Surface "*"; > s = news; > For i In {0 : #ss[]-1} > Compound Surface(s+i) = ss[i]; > EndFor > > bl = newl; > bs = news; > > Field[1] = MathEval; > Field[1].F = "0.1"; > > Background Field = 1; > > Mesh.CharacteristicLengthExtendFromBoundary = 0; > > Physical Surface("Side-01") = {s}; > Physical Surface("Top") = {s+1}; > Physical Surface("Side-02") = {s+2}; > Physical Surface("Outlet") = {s+3}; > Physical Surface("Bottom") = {s+4}; > Physical Surface("Inlet") = {s+5}; > > sl = newsl; Surface Loop(sl) = {s:s+5}; > vo = newv; Volume(vo) = {sl}; > > //Physical Volume("V_Fluid") = {vo}; > > pp[] = Point "*"; > > Field[2] = BoundaryLayer; > //Field[2].AnisoMax = 60; > Field[2].FacesList = {s:bs-1}; > Field[2].EdgesList = {l:bl-1}; > Field[2].NodesList = {pp[0]:pp[7]}; > //Field[2].FanNodesList = {pp[0]:pp[7]}; > //Field[2].IntersectMetrics = 0; > //Field[2].Quads = 0; > //Field[2].hfar = 0.1; > Field[2].hwall_n = 0.025; > //Field[2].hwall_t = 0.1; > Field[2].ratio = 1.1; > Field[2].thickness = 0.05; > BoundaryLayer Field = 2; > //Background Field = 2; > > ---------------------------------------------- > > -- > Praveen Kumar R | Technical Manager > Centre for Computational Technologies - CCTech > 1 Akshay Residancy | 50 Anand Park | Aundh | Pune | 411007 | India > Ph: +91 20 40098381/82 | M: +91-9923406816 | www.cctech.co.in > CCTech – "Transforming human life by democratization of technology" > > > <duct.geo><duct.stl><BL-issue.JPG>_______________________________________________ > gmsh mailing list > gmsh@onelab.info > http://onelab.info/mailman/listinfo/gmsh -- Prof. Christophe Geuzaine University of Liege, Electrical Engineering and Computer Science http://www.montefiore.ulg.ac.be/~geuzaine Free software: http://gmsh.info | http://getdp.info | http://onelab.info _______________________________________________ gmsh mailing list gmsh@onelab.info http://onelab.info/mailman/listinfo/gmsh