Exemple #1
0
def front_mesh_symmetric(res=0.025):
    """
    Creates a donut mesh with symmetry line through y = c_y
    """
    geometry = Geometry()
    mesh_r = width_scale*res
    c = geometry.add_point((c_x,c_y,0))
    
    # Elliptic obstacle
    p1 = geometry.add_point((c_x-r_x, c_y,0))
    p2 = geometry.add_point((c_x+r_x, c_y,0))
    # embed()
    arc_1 = geometry.add_circle_arc(p1, c, p2)
    arc_2 = geometry.add_circle_arc(p2, c, p1)

    # Surrounding mesh
    p3 = geometry.add_point((c_x-r_x-mesh_r, c_y,0))
    p4 = geometry.add_point((c_x+r_x+mesh_r, c_y,0))
    arc_5 = geometry.add_circle_arc(p3, c, p4)
    arc_6 = geometry.add_circle_arc(p4, c, p3)
    line_front = geometry.add_line(p3, p1)
    line_back = geometry.add_line(p2, p4)    
    surface_top = geometry.add_line_loop([line_front, arc_1, line_back, -arc_5])
    surface_bottom = geometry.add_line_loop([line_front, -arc_2, line_back,
                                             arc_6])

    obstacle_loop = geometry.add_line_loop([arc_1, arc_2])
    outer_loop = geometry.add_line_loop([arc_5,arc_6])
    
    top = geometry.add_plane_surface(surface_top)
    bottom = geometry.add_plane_surface(surface_bottom)
    geometry.add_physical_surface([top, bottom],label=12)
    geometry.add_physical_line(obstacle_loop.lines, label=inner_marker)
    geometry.add_physical_line(outer_loop.lines, label=outer_marker)

    # Create refined mesh around geometry
    field = geometry.add_boundary_layer(edges_list=obstacle_loop.lines,
                                        hfar=res, hwall_n=res/3,
                                        thickness=0.1*mesh_r)
    geometry.add_background_field([field])

    # Generate mesh
    (points, cells, point_data,
     cell_data, field_data) = generate_mesh(geometry, prune_z_0=True,
                                            geo_filename="meshes/test.geo")

    # Save mesh and mesh-function to file
    meshio.write("multimesh_1.xdmf", meshio.Mesh(
        points=points, cells={"triangle": cells["triangle"]}))
    
    meshio.write("mf_1.xdmf", meshio.Mesh(
        points=points, cells={"line": cells["line"]},
        cell_data={"line": {"name_to_read":
                            cell_data["line"]["gmsh:physical"]}}))
    import os
    os.system("mv multimesh_1.* meshes/")
    os.system("mv mf_1.* meshes/")
Exemple #2
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def background_mesh(res=0.025):
    """
    Create rectangular background mesh for the Poisson problem
    """
    geo = Geometry()
    # Create points for square with two inlets and one outlet
    points = []
    points.append(geo.add_point((0, 0, 0), res))
    points.append(geo.add_point((1, 0, 0), res))
    points.append(geo.add_point((1, 1, 0), res))
    points.append(geo.add_point(outlet[1], res))
    points.append(geo.add_point(outlet[0], res))
    points.append(geo.add_point((0, 1, 0), res))
    points.append(geo.add_point(inlet1[1], res))
    points.append(geo.add_point(inlet1[0], res))
    points.append(geo.add_point(inlet0[1], res))
    points.append(geo.add_point(inlet0[0], res))
    # Connect points as lines
    lines = []
    for i in range(len(points) - 1):
        lines.append(geo.add_line(points[i], points[i + 1]))
    lines.append(geo.add_line(points[-1], points[0]))
    # Create geometry
    line_loop = geo.add_line_loop(lines)
    square = geo.add_plane_surface(line_loop)

    # Create cell and facet function
    wall_lines = lines[0:3] + lines[4:6] + [lines[7]] + [lines[9]]
    inlet0_lines = [lines[8]]
    inlet1_lines = [lines[6]]
    outlet_lines = [lines[3]]
    geo.add_physical_surface([square], label=12)
    geo.add_physical_line(inlet0_lines, label=inlet0_marker)
    geo.add_physical_line(inlet1_lines, label=inlet1_marker)
    geo.add_physical_line(outlet_lines, label=outlet_marker)
    geo.add_physical_line(wall_lines, label=wall_marker)

    # Create mesh
    (points, cells, point_data, cell_data,
     field_data) = generate_mesh(geo, prune_z_0=True)  #,
    #geo_filename="meshes/tmp.geo")

    meshio.write(
        "meshes/multimesh_0.xdmf",
        meshio.Mesh(points=points, cells={"triangle": cells["triangle"]}))

    meshio.write(
        "meshes/mf_0.xdmf",
        meshio.Mesh(points=points,
                    cells={"line": cells["line"]},
                    cell_data={
                        "line": {
                            "name_to_read": cell_data["line"]["gmsh:physical"]
                        }
                    }))
from dolfin.fem import assemble_scalar
from dolfin import FunctionSpace, TrialFunction, TestFunction, DirichletBC, Function, solve, cpp, fem

geom = Geometry()

mesh_ele_size = .02
p1 = geom.add_point([0.0, 0.0, 0], lcar=mesh_ele_size)
p2 = geom.add_point([0.0, 1.0, 0], lcar=mesh_ele_size)
p3 = geom.add_point([1.0, 1.0, 0], lcar=mesh_ele_size)
p4 = geom.add_point([1.0, 0.0, 0], lcar=mesh_ele_size)
p5 = geom.add_point([0.2, 0.5, 0], lcar=mesh_ele_size)
p6 = geom.add_point([0.2, 0.7, 0], lcar=mesh_ele_size)
p7 = geom.add_point([1.0, 0.5, 0], lcar=mesh_ele_size)
p8 = geom.add_point([1.0, 0.7, 0], lcar=mesh_ele_size)

l1 = geom.add_line(p1, p4)
l2 = geom.add_line(p3, p2)
l3 = geom.add_line(p2, p1)
l4 = geom.add_line(p7, p5)
l5 = geom.add_line(p5, p6)
l6 = geom.add_line(p6, p8)
l7 = geom.add_line(p4, p7)
l8 = geom.add_line(p7, p8)
l9 = geom.add_line(p8, p3)

ll1 = geom.add_line_loop(lines=[l2, l3, l1, l7, l4, l5, l6, l9])
ps1 = geom.add_plane_surface(ll1)

ll2 = geom.add_line_loop(lines=[l6, -l8, l4, l5])
ps2 = geom.add_plane_surface(ll2)
from pygmsh.built_in.geometry import Geometry
from pygmsh import generate_mesh
import meshio
import dolfin
import dolfin.io

geom = Geometry()

mesh_ele_size = .1
p0 = geom.add_point([0, 0, 0], lcar=mesh_ele_size)
p1 = geom.add_point([1, 0, 0], lcar=mesh_ele_size)
p2 = geom.add_point([1, 1, 0], lcar=mesh_ele_size)
p3 = geom.add_point([0, 1, 0], lcar=mesh_ele_size)

l0 = geom.add_line(p0, p1)
l1 = geom.add_line(p1, p2)
l2 = geom.add_line(p2, p3)
l3 = geom.add_line(p3, p0)

ll = geom.add_line_loop(lines=[l0, l1, l2, l3])
ps = geom.add_plane_surface(ll)

# Tag line and surface
geom.add_physical(l3, label=444)
geom.add_physical(ps, label=456)

print("\n".join(geom._GMSH_CODE))

mesh = generate_mesh(geom)
points, cells, cell_data = mesh.points, mesh.cells, mesh.cell_data
meshio.write("input/mesh_2d.xdmf",
Exemple #5
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def front_mesh(res=0.025):
    geometry = Geometry()
    mesh_r = width_scale * res
    c = geometry.add_point((c_x, c_y, 0))

    # Elliptic obstacle
    p1 = geometry.add_point((c_x - r_x, c_y, 0))
    p2 = geometry.add_point((c_x + r_x, c_y, 0))
    p12 = geometry.add_point((c_x, c_y + 1.4 * r_x, 0))
    p21 = geometry.add_point((c_x, c_y - 1.4 * r_x, 0))

    arc_1 = geometry.add_spline([p1, p12, p2])
    arc_2 = geometry.add_spline([p2, p21, p1])
    # arc_1 = geometry.add_circle_arc(p1, c, p2)
    # arc_2 = geometry.add_circle_arc(p2, c, p1)

    # Surrounding mesh
    p3 = geometry.add_point((c_x - r_x - mesh_r, c_y, 0))
    p4 = geometry.add_point((c_x + r_x + mesh_r, c_y, 0))
    p34 = geometry.add_point((c_x, c_y + 1.4 * r_x + mesh_r, 0))
    p43 = geometry.add_point((c_x, c_y - 1.4 * r_x - mesh_r, 0))
    arc_5 = geometry.add_spline([p3, p34, p4])
    arc_6 = geometry.add_spline([p4, p43, p3])

    # arc_5 = geometry.add_circle_arc(p3, c, p4)
    # arc_6 = geometry.add_circle_arc(p4, c, p3)
    line_front = geometry.add_line(p3, p1)
    line_back = geometry.add_line(p2, p4)
    surface_top = geometry.add_line_loop(
        [line_front, arc_1, line_back, -arc_5])
    surface_bottom = geometry.add_line_loop(
        [line_front, -arc_2, line_back, arc_6])

    obstacle_loop = geometry.add_line_loop([arc_1, arc_2])

    top = geometry.add_plane_surface(surface_top)
    bottom = geometry.add_plane_surface(surface_bottom)
    geometry.add_physical_surface([top, bottom], label=12)
    geometry.add_physical_line(obstacle_loop.lines, label=inner_marker)

    # Create refined mesh around geometry
    field = geometry.add_boundary_layer(edges_list=obstacle_loop.lines,
                                        hfar=res,
                                        hwall_n=res / 3,
                                        thickness=2 * res)
    geometry.add_background_field([field])

    # Generate mesh
    (points, cells, point_data, cell_data,
     field_data) = generate_mesh(geometry,
                                 prune_z_0=True,
                                 geo_filename="meshes/test.geo")

    # Save mesh and mesh-function to file
    meshio.write(
        "meshes/multimesh_1.xdmf",
        meshio.Mesh(points=points, cells={"triangle": cells["triangle"]}))

    meshio.write(
        "meshes/mf_1.xdmf",
        meshio.Mesh(points=points,
                    cells={"line": cells["line"]},
                    cell_data={
                        "line": {
                            "name_to_read": cell_data["line"]["gmsh:physical"]
                        }
                    }))