Description

Before you start generating a grid with Pointwise (or by any other means), you should first consider several aspects related to the analysis to be performed. This will save you a lot of time while avoiding costly false starts and rework.

 

Tip: Spending a little time up front to plan your project and make sure the grid meets your goals in the most efficient way will save a lot of time and resources downstream.

Define the Modeling Goals

  • What specific results are required from the analysis? Are you just looking for general flow patterns or more detailed information about pressure, heat transfer, and separation locations in the flow field?
  • What degree of accuracy is required? Are you looking for trends or absolutes?
  • How much time do you have to complete the analysis? Do you have the time (both labor hours and computer) to analyze the complete system, or can you obtain meaningful results by analyzing only the component of interest?

Identify Your Grid's Constraints

  • What types of grid topologies can your analysis software handle?
  • What is the maximum number of grid points you can use? What is the maximum number of grid blocks you can use?

Plan the Grid

  • What grid topologies will work best?
  • Which areas will require a finer grid to accurately resolve a boundary layer, shock wave or other flowfield feature? Which areas can be covered with a coarser grid?
  • Are there components of the geometry that will be changed for additional analyses? Can they be isolated in the grid for later ease in editing?

Outline of the Pointwise Process

After you have planned your grid and familiarized yourself with Pointwise's terminology and command structure, you are ready to begin generating your grid. Pointwise is designed for you to flow through the grid generation process in a specific order, proceeding from grid curves (the one dimensional grid elements), through surface grids (the two dimensional grid elements), to volume grids (the three dimensional grid elements). This process allows Pointwise to automate many of the grid topology and dimension bookkeeping tasks you would have to keep track of yourself otherwise.

The basic steps you will follow are listed below. Some of the steps are optional, as noted.

  1. Choose the analysis software you will use and whether the grid will be 2D or 3D.
  2. Create or import the geometry model (database). (optional)
  3. Create the curves (connectors) that define the boundaries of surface grids.
  4. Distribute grid points along the connectors.
  5. Pick closed loops of connectors to define surface grids (domains).
  6. Apply a grid method to improve the distribution of surface grid points. (optional)
  7. Pick closed shells of domains to define volume grids (blocks).
  8. Apply a grid method to improve the distribution of volume grid points. (optional)
  9. Set analysis software boundary conditions. (optional)
  10. Export analysis software data files.
  11. Save the Pointwise Project file.
 

Note: For 3D grids, select blocks for exporting to a selected CAE. Otherwise, select domains for the export instead.

While the detailed operations performed in each of these steps will vary for each grid you build, you will always follow these basic steps in this general order. We also recommend you create some of your domains (surface grids) as soon as you have enough connectors created. This will allow you to see immediately whether or not the distribution of grid points you applied to your connectors results in a good domain surface grid. By doing this, you will be able to identify and correct potential problems at the earliest possible stage in the grid generation process resulting in a better final grid.