Getting Started
Setting up your Ennova Work Space
Ennova is a Client/Server application. As a user you can:
• run both the Client and the Server on your own computer
or,
• run the Client on your own computer and use a larger computer or even cluster to run the Server to compute very large meshes.
Models and any associated files will be stored on the Server or host computer. For example, if you are executing Ennova as Client on a notebook and Server on a hosted Linux cluster, your data files will always be stored on the host Server, not your local notebook. At no point does any file from Ennova get stored on the local computer.
Please skip the next step if running the Client and the Server on the SAME computer.
Remote Client Linux Server / Client Windows
• If your Ennova is running on a Linux server, to run the client on your own computer you must enable SSH login without a password on your computer.
• Make sure you have a valid login to the host computer (the server where Ennova is running). Contact your IT department if needed. Obtain the IP address for this computer.
• Setup your SSH for login to the host computer without a password login using private keys.
• Verify you can login to your account via SSH without a password prompt successfully.
• Note: If you are not familiar with Linux you may require IT help in completing these tasks.
Opening Files in Ennova
• Make a new directory on your host/server computer in your account. Download your file to this directory.
• If the Client and the Server are on the same computer, navigate to the directory and open the file. If the Server is remote, choose the IP of that computer from the list and navigate as usual. Except for this step, there are no differences running Ennova whether the Server is local or remote.
Ennova Interface
Ennova’s supported platforms are Microsoft Windows XP/Vista/7, Red Hat Enterprise Linux 6.1, and Ubuntu 10.04.
Navigating Ennova – Quick Tips
• The top tabs Geometry / Mesh give the respective views of the model.
• RMB (Right Mouse Button) - Ennova is RMB sensitive and most likely the next command needed will be right there. Otherwise icon menus are always available.
• Hide all surfaces is the most convenient view of the topology.
Edge Display and Definition
• Ennova Topology is best thought of as how surfaces are connected to form volumes. Ultimately in CFD we are after a volume to mesh, so the first stage in constructing an Ennova mesh is to “Repair” the geometry until the required number of complete CFD volumes is present.
• In this example we wish to analyze the airflow over Batman’s car so we are working towards a single exterior CFD volume.
• Surfaces are always connected at their edges, or at least 1 surface is. So in Ennova we pay a lot of attention to working with the edges.
• Edges that are free in space are BLUE. They are not associated with any surface geometry.
• Edges of a surface connected to a single surface are RED. The surface may be geometrically close to another surface but if the edge is RED it is physically not glued to the next surface.
• Edges that are connected to two surfaces are BLACK. If we are looking for one volume then all edges will be BLACK for the volume to be valid . For a single volume CFD analysis we continue to “Repair” a model until all edges are BLACK. Until all edges are BLACK our work is not finished.
• Edges that are connected to more than 2 surfaces are YELLOW Volumes which share a face will have YELLOW edges. Hence YELLOW and BLACK are valid edges if multiple connecting volumes are present. On a closed volume, generally YELLOW edges form closed loops. If a YELLOW edge is by itself this can be an indication of geometry in need of repair.
• RED edges are generally not valid unless internal baffle surfaces are present.
CAD Repair Tips
Begin with CAD Repair, and repair the geometry until valid Ennova CFD volumes are created. Many times this may be just one volume. CAD Repair is a combination of automatic procedures and manual fixes to problem areas.
The following are the typical steps required:
· Defeature the geometry if needed. Sometimes the CAD data has features, usually small items that are not needed for the CFD analysis. Use the Ennova Defeature command to remove these automatically.
· Add/Modify the topology manually for any solver or user desired mesh requirements such as anisotropic meshing of critical aerodynamics components.
· Create a surface mesh for the volume(s).
· Modify surface mesh sizing to suit analysis.
· Identify groups/surfaces with extruding viscous prism layers and mesh prism layers.
· Finally, fill in volume mesh with tetra background mesh.
Typically 90% of the user work is in the CAD repair for normal CAD data. Often this is so because the CAD data has not been produced for CFD analysis but rather manufactured where geometric tolerances are up to 1000 x bigger than required for CFD. For this reason much of the Ennova development has been focused on automating geometry cleanup.
