In order for a boundary condition to be assigned later on, each feature must be a face of the geometry. Note that for features such as circular inlets on a round face, you cannot use a hole but rather define it as a cylinder and build the rest of the profile around it until the desired shape is achieved. circle, these will need to be defined separately to the outer layer of the domain. only half of a face, or a particular shape e.g. If you have inlets which do not run the full width of the domain e.g. Begin by sketching the base of your computational domain, this flat plane sketch will be extruded into a 3-dimensional shape later on. Once you know this, open a new drawing file inside a conveneient CAD program, in this case it will be solidWorks. It is important to know the exact dimensions of the geometry you wish to use for your case including where the main features lie such as inlets, outlets and which faces are solid walls. In this case, I will be following an example which can be performed using software available in Mechanical enginnering, although the process is much the same for any combination of programs. OpenFoam has a wide range of tools from which you can import meshes from many of the more well-known cfd packages available on the market. Importing a mesh: There are many other mesh generation applications or priograms available to choose from, some are opensource such as gmesh whilst others are part of a consumer software package such as Fluent’s ICEM. This will give you an overview of the mesh including cell numbers, types and any errors which may have occured during the building process or which may affect the simulation. The blockMesh file is located in the ‘polymesh’ directory of the ‘constant’ folder in the openFoam case, to build the mesh, simple type the command: The lack of any kind of visual interface means that even the simplest errors are difficult to spot without viewing your mesh in an application such as paraFoam, the way in which the blocks of the mesh are defined can be found in the userguide and are not too taxing for simple and small geometries, however when modelling more complex shapes with small details requires far more effort. There are two ways to go about this, the first is to use OpenFoams own application, blockmesh and the second is to import a file meshed using an external piece of software which can then be converted for use with OpenFoam.īlockMesh: In my personal experience with blockMesh, it is both time-consuming and difficult to understand when starting out with this software. Once you have decided which solver will be best for your particular case, the first thing to do is to create the computational domain and mesh it. Useful information on how to install the required modules and the submission of scripts to the queuing system can be found at the bottom of this page. OpenFoam has several different types of solvers, a complete list of which can be found inside the user guide at: The ‘system’ folder, which contains the control dictionary which handles the time step and solver settings and the files used to control the solver schemes and tolerances of the variables.īefore setting up any of the fields or solver settings, it is important to understand which type of solver your particular case will require. The ‘constant’ folder, this contains the transport properties ditionary, the settings for the particular RANS/LES model being used and the ‘polymesh’ folder which stores the blockMesh file used in the mesh creation stage. The ‘0’ time folder, this is where the files which contain the boundary and initial conditions for each of the variables being calculated are stored. Overview of case setup #Īn OpenFoam case will consist of 3 separate directories: It also assumes you’re using the default module environment, and haven’t altered compilers being used. Usage described in this document assumes you’re using v1906 on ARC4, and may require some adjustment if using other versions, or using ARC3. Versions older than v1906 may behave slightly differently, such as not requiring source $FOAM_SRC_FILE but use of these versions is not covered by this documentation.
0 Comments
Leave a Reply. |