Tutorial 1: Getting Started

Tutorial 1. Part 1. Basic concepts 2-D case

Tutorial 1. Part 1. Basic concepts 2-D case

What you will learn

Step 1. Loading the Geometry

Load up the Tutorial 1 geometry by directly double clicking on the Tutorial_1.fra file, or by clicking on the topo button in the Topology menu on the top menu bar and load in the TIL (Topology Input Language) file by clicking on Tutorial_1.fra.

Step 2. Working in 2D

Put GridPro in 2-D mode by clicking on dim=2 in the menu bar at the top.

Step 3. Zooming-in

Zoom-in by right clicking on the mouse and dragging a box around the geometry which consists of a center circle and four walls as in the picture below.

Step 4. Turning off the Global Axis and Cut-Plane

The dotted straight lines represent the X and Y of the Global Axis and the rectangular white square the Cut-Plane. Since we are working in 2D and our geometry is relatively simple let’s reduce the screen clutter by shutting off the axis and the Cut-Plane in the SHOW menu on the Command Panel to the right (we will learn more about the Cut-Plane in a later tutorial).

Step 5. Meshing Objectives

Understanding basic topology design is important in learning how to create a computational mesh. Much of the mesh in GridPro is automatic, however, the user must input basic topology information. This information exists in the form of points and edges that are “wrapped” around the geometry of interest. GridPro always makes a mesh that focuses on the most important part of the geometry, such as the boundary layer, that will remain refined and nearly orthogonal ensuring accurate and quick CFD results.

Step 6. Creating Outer Edges of the Topology

The topology needs to be “wrapped” around the geometry. The wrap is created by connecting the corners with edges. Press down the E on the keyboard and make the edges by clicking on the upper left corner, and while continuing to press E, click the upper right corner.

Step 7. Creating the Inner Edges of the Topology

Once the outer edges are defined, a wrap must be created around the cylinder. The objective is to “box-in” the cylinder by placing Edge Sheets through the outer topology. Once a box is created around the cylinder it will be used to “wrap” the geometry. While holding down I on the keyboard, place the cursor about 1/3 of the way from the upper left corner of the top edge and click the left mouse button.

Step 8. Creating the Wrap

The wrap is created by grouping the four inner corners of the topology and extruding it a desired distance inward. A group consists of a certain number of edges and corners chosen by the user. In this case an inner wrap around the cylinder is necessary.

Step 9. Wrapping

To wrap the topology make sure that the group 1 button is on and click on the wrp button in the TOPO sub-command panel to pull down the wrap options.

Step 10. Surface Assignments

Once the wrap is created we are ready to assign the corners to the surface. In doing so, we need to keep two things in mind. First, a well defined mesh needs to surround the circle to capture the boundary layer flow. Second, a well defined box-like structure defined by the walls surrounding the circle needs to encompass the mesh region.

Step 11. Creating the Mesh

Now that you have created the topology and assigned the surfaces, let’s create the mesh. Go to the Top Menu Bar and left click on the topo button to pull down the topo menu and click on Ggrid Start to begin the meshing process.