Description

refine is a 2D and 3D mesh adaptation tool implemented in the C language.

Mesh adaptation mechanics are provided where the primary target is linear and curved simplex (triangle and tetrahedra) meshes. A limited capability to store, modify, and insert mixed-element types is also provided. Typical use is via an executable that interacts with files, and linking to a library form is also available. Mesh adaptation metrics can be computed by reconstructing gradients and Hessians from a field. Visualization files and multiple mesh formats can be exported. Solutions can be interpolated between meshes. The distance to lower-dimensional elements can be computed. Interfaces are available to multiple geometry sources and an internal surrogate geometry source. Parallel execution is supported with partitioning and load balancing. Solution fields are provided to verify the mesh adaptation process.

Quick Start Compile from Git Repo and Basic Usage

refine can function without dependencies, but the typical use cases of parallel execution and geometry evaluation require an MPI implementation and Engineering Sketch Pad (ESP). A native implementation of a recursive coordinate bisection partition algorithm is included, but better results are expected with ParMETIS. Initial mesh generation assumes TetGen or AFLR is in the shell path. Configuration and compilation is supported with Autoconf and CMake.

Automake 1.7 (or later) and Autoconf 2.53 (or later):

 ./bootstrap
 mkdir -p build
 cd build
 ../configure --prefix=`pwd` \
   --with-mpi=/mpi/path \
   --with-parmetis=/parmetis/path \
   --with-EGADS=/egads/path \
   --with-OpenCASCADE=/opencascade/path
 make
 make install

See the INSTALL file in the top directory or ./configure --help for additional build instructions.

CMake 3.0 (or later):

 mkdir -p build
 cd build
 cmake .. -DCMAKE_INSTALL_PREFIX=`pwd` \
   -DCMAKE_PREFIX_PATH="/mpi/path;/parmetis/path;/egads/path;/opencascade/path"
 make
 make install

Usage

The installed bin directory will include the ref executable. Invoking ref with no arguments will list available subcommands. Help on a particular subcommand is available via a -h, i.e., ref adapt -h. If MPI is provided, refmpi will allow for parallel execution. If ESP is provided, ref and refmpifull includes EGADS built with OpenCASCADE and refmpi includes EGADSlite.

Executable	MPI	EGADS	EGADSlite
ref		X
refmpi	X		X
refmpifull	X	X

Examples

The following examples assume that ref is in your shell path. mpiexec ... refmpi or mpiexec ... refmpifull can be substituted for ref in each of these examples if MPI and/or ESP is configured. The .meshb and .solb file extensions are used generically. Other formats are supported, e.g., AFLR *.ugrid.

Bootstrapping Mesh Adaptation on an EGADS Model

An .egads file can be dumped from OpenCSM in the ESP package.

ref bootstrap project.egads

or

mpiexec ... refmpifull bootstrap project.egads

which assume that tetgen is in your shell path or aflr3 is in your shell path with --mesher aflr option. A project-vol.meshb is output that includes the surface mesh, volume mesh, mesh-to-geometry associativity, and EGADSlite data.

Mesh Adaptation

The mesh is adapted with

ref adapt input.meshb -x output.meshb [-m metric.solb] [-g geometry.egads]

or

mpiexec ... refmpi adapt input.meshb -x output.meshb [-m metric.solb]

where a surface curvature metric is used if the -m argument is not present.

Multiscale Metric for Control of Interpolation Error in Lp-norm

In conjunction with the Unstructured Grid Adaptation Working Group, an implementation of the multiscale metric is provided.

ref multiscale input.meshb scalar.solb complexity output-metric.solb

or

mpiexec ... refmpi multiscale input.meshb scalar.solb complexity output-metric.solb

Field Interpolation

The fields in a .solb file paired with a donor mesh can be interpolated to a receptor mesh. This utility can be executed in serial or parallel.

ref interpolate donor-mesh.ext donor-field.solb receptor-mesh.ext receptor-field.solb

or

mpiexec ... refmpi interpolate donor-mesh.ext donor-field.solb receptor-mesh.ext receptor-field.solb

where the output is receptor-field.solb.

Distance to surface elements

The distance to surface elements with a non-slip boundary condition is used by many turbulence models. These no-slip face ids are specified with --viscous-tags <comma-separated list> or --fun3d-mapbc fun3d_format.mapbc

ref distance mesh.ext distance.solb [face id option]

or

mpiexec ... refmpi distance mesh.ext distance.solb [face id option]

where the wall distance is distance.solb.