) * v ( '+' ) * dS ( 13 ) # set homogeneous Dirichlet boundary conditions on the rectangle boundaries # the tag 11 referes to the horizontal edges, the tag 12 refers to the vertical edges DirBC = DirichletBC ( V, 0, ) # define u to contain the solution to the problem under consideration u = Function ( V ) # solve the variational problem solve ( a = L, u, bcs = DirBC, solver_parameters = )Ī python script version of this demo can be found here. From firedrake import * # load the mesh generated with Gmsh mesh = Mesh ( 'immersed_domain.msh' ) # define the space of linear Lagrangian finite elements V = FunctionSpace ( mesh, "CG", 1 ) # define the trial function u and the test function v u = TrialFunction ( V ) v = TestFunction ( V ) # define the bilinear form of the problem under consideration # to specify the domain of integration, the surface tag is specified in brackets after dx # in this example, 3 is the tag of the rectangle without the disc, and 4 is the disc tag a = 2 * dot ( grad ( v ), grad ( u )) * dx ( 4 ) + dot ( grad ( v ), grad ( u )) * dx ( 3 ) + v * u * dx # define the linear form of the problem under consideration # to specify the boundary of the boundary integral, the boundary tag is specified after dS # note the use of dS due to 13 not being an external boundary # Since the dS integral is an interior one, we must restrict the # test function: since the space is continuous, we arbitrarily pick # the '+' side. write ( 'naca_boundary_layer_2d.msh' ) 144 145 if '-nopopup' not in sys. optimize ( 'HighOrderFastCurving' ) 141 gmsh. generate ( 2 ) 136 137 # 2nd order + fast curving of the boundary layer + optimization 138 if order2 : 139 gmsh. setAsBoundaryLayer (f ) 133 134 # generate the mesh 135 gmsh. setNumbers (f, 'FanPointsList', ) 131 132 gmsh. setNumber ( 'Mesh.BoundaryLayerFanElements', 7 ) 130 gmsh. setNumber (f, 'Thickness', 0.01 ) 127 if not rounded : 128 # create a fan at the trailing edge 129 gmsh. setNumbers (f, 'CurvesList', curv ) 123 gmsh. addPoint (- 1, - 1, 0, lc2 ) 110 p2 = gmsh. The examples given here use the GMSH scripting language, specifying a 'geo' geometry file that GMSH processes to create an 'msh' mesh file. synchronize () 104 105 else : 106 # in 2D, boundary layers can also be specified as a meshing constraint, 107 # through the BoundaryLayer field this is quite a bit more general, as it 108 # handles intersections between several boundary layers, fans, etc. addCurveLoop ( for c in extbl ]) 91 92 # connect it with the exterior surface 93 p1 = gmsh. getEntities ( 1 ), 87 * N, d, True ) 88 89 # create curve loop with "top" curves of the boundary layer 90 cl2 = gmsh. append (d - (-d ) * r **i ) 85 print (d ) 86 extbl = gmsh. synchronize () 77 # a boundary layer can be created through extrusion using the built-in CAD 78 # kernel: this creates topological entities that will be filled with a 79 # discrete geometry (a mesh extruded along the boundary normals) during mesh 80 # generation 81 N = 10 # number of layers 82 r = 2 # ratio 83 d = # thickness of first layer 84 for i in range ( 1, N ): d. addCurveLoop (curv ) 74 75 if by_extrusion : 76 gmsh. addLine (pt, pts )) 69 70 # rotate the profile 71 gmsh. addCircleArc (pts, c, pts )) 65 else : 66 pt = gmsh. ![]() addPoint ( 0.9985510, 0.0000000, 0, lc1 ) 64 curv. PDF On Feb 4, 2013, Roman Putanowicz published Box3DHole - sample GMSH script for generation of structured 3D mesh Find, read and cite all the research. addSpline (pts )) 60 61 if rounded : 62 # circle as trailing edge 63 c = gmsh. addPoint (naca, -naca, 0, lc1 )) 57 pts. 11 12 # create the boundary layer by extrusion, or as a mesh constraint? 13 by_extrusion = False 14 15 # rounded trailing edge? 16 rounded = True 17 18 # base mesh sizes 19 fact = 1 20 lc1 = 0.01 * fact 21 lc2 = 0.3 * fact 22 23 # generate curved mesh? 24 order2 = False 25 26 # xy coordinates of top part of NACA 0012 profile 27 naca = 49 50 # create profile from points 51 pts = 52 l = len (naca ) 53 for i in range ( 0, l // 2 ): 54 pts. add ( "NACA 0012" ) 8 9 # incidence angle 10 incidence = -math. ![]() As a special service "Fossies" has tried to format the requested source page into HTML format using (guessed) Python source code syntax highlighting (style: standard) with prefixed line numbers.Īlternatively you can here view or download the uninterpreted source code file.ġ import gmsh 2 import sys 3 import math 4 import numpy as np 5 6 gmsh.
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