Symscape

Simulate internal flow by creating two boxes, stitching them together, and specifying the physical conditions for your simulation. Then view velocity vectors and particle tracks inside the volume.

Goals

In this tutorial, you will learn how to:

• Create a box
• Translate geometry
• Delete faces and stitch two pieces of geometry together
• Specify physical conditions for a simulation, in this case including the fluid inside the geometry and the properties of the outer surface of the geometry (walls, inlet, outlet)
• Specify the accuracy of the results you require
• Generate velocity vectors
• Generate particle tracks

Assumptions

1. You have activated the SymLab Builder and SymLab Panel Flow add-ons, or SymLab Professional.
2. You are familiar with SymLab essentials.

Create Two Boxes

Select the Geometry Tool Palette. Select the Volumes->Box tool. Drag and drop the Volumes->Box tool onto the View Window. Select Done to create a box.

Drag and drop the Volumes->Box tool onto the View Window again. Double click sim in the Select dialog and select Done to create a 2nd box.

Combine the Two Boxes into a Single Volume

To combine the 2 boxes into a single volume, you will first translate one of the boxes so that only one of its faces is coincident with the other box. You will then delete the 2 coincident faces of the boxes, and finally stitch the 2 boxes together to create a single volume.

To translate one of the boxes in the y-direction, select the Transforms->Translate tool. Set the parameters in the Properties Panel to [0 10 0] and press Enter on the keyboard to apply the changes.

Drag and drop the Transforms->Translate tool onto an edge of one of the boxes in the View Window. Double-click volume_1 in the Select dialog and select Done to translate the 2nd box 10m in the y-direction. Click on the Fit All icon in the toolbar so that you can see the 2 boxes in the View Window. To rotate the view, left-click-and-drag the mouse in the View Window until the boxes are in the approximate orientation shown below.

To select the 1st coincident face to be deleted, right-click on one of the coincident edges, as shown below.

In the Select dialog, select face_8 or whichever face is the 1st coincident face. (See below for the face that should be highlighted.)

Click OK in the Select dialog and then select Select/Deselect from the menu.

To select the 2nd face to be deleted, right-click on the same edge again (as shown above) and then select face_3 (or again, whichever face is the 2nd coincident face) in the Select dialog. Click OK and then select Delete Multiple from the menu to delete the 2 coincident faces.

To stitch all of the remaining faces together into a volume, select the Volumes->Stitch tool, and drag and drop it onto the background of the View Window. Double-click Faces in the Select dialog and then select Done from the menu.

Specify the Fluid Conditions

Select the Physics Tool Palette. Drag and drop the Substances->Air tool onto an edge of the volume. Select Done to set air as the fluid inside the volume.

Set the Properties of the Outer Surface of the Volume

Drag and drop the Conditions->Wall tool onto an edge of the volume. Double-click volume_2->Faces in the Select dialog and select Done to create walls on the outer surfaces of the volume.

A wall is a solid surface through which fluid cannot flow.

To create an inlet, drag and drop the Conditions->Inlet tool onto an edge of the face shown below. Select that face in the Select dialog (the edges of the face will be highlighted), click OK, and then select Done to create the inlet.

To create an outlet, drag and drop the Conditions->Outlet tool onto an edge of the face shown above. Select that face in the Select dialog, click OK, and then select Done to create the outlet.

Specify the Accuracy You Require for Your Results

Select the Conditions->Accuracy tool. Verify that Low is selected for the Accuracy in the Properties panel.

Drag and drop the Accuracy tool onto an edge of the volume. Double-click volume_2->Faces in the Select dialog and select Done to set the accuracy of the calculation.

Set the Reference Speed for the Simulation

The reference speed is required for internal flows because initially there is no obvious flow direction inside the volume. SymLab uses the reference speed to calculate pressure coefficients later in this tutorial.

Select the Conditions->Speed Reference tool. Notice that the Speed in the Properties panel is set to 1m/s.

Drag and drop the Conditions->Speed Reference tool onto the background of the View Window. Double-click on Volumes in the Select dialog and select Done to set the reference speed as 1m/s.

Calculate the Velocity of Air Within the Volume

Select the Results Tool Palette. Drag and drop the Vector Fields->Velocity tool onto an edge of the volume in the View Window. Double-click volume_2->Faces in the Select dialog and select Color Map to create contours of velocity magnitude on the inner surface of the volume.

SymLab will solve for the flow through the volume automatically and then display the contours.

To display velocity vectors, drag and drop the Vector Fields->Velocity tool onto an edge of the volume. Double-click volume_2->Faces in the Select dialog and select Arrows to create arrows colored by velocity magnitude on the inside surface of the volume.

To make the arrows larger, left-click on Arrows in the bottom right corner of the View Window to select the arrows in the View Window. In the Properties panel, set the Scale to 2 and press Enter on the keyboard to scale the arrows.

View Particles Tracks Through the Volume

To see the particles tracks more clearly, you will first delete the velocity vectors from the box.

To delete the velocity vectors, right-click on Arrows in the bottom right corner of the View Window and select Delete Velocity.

To delete the velocity magnitude contours, right-click on Color Map at the bottom of the View Window and select Delete Velocity:... (which stands for Velocity:Magnitude).

To display particle tracks, drag and drop the Vector Fields->Velocity tool onto an edge of the inlet in the View Window. Select the inlet face in the Select dialog, click OK, and select Set Particles Target. Right-click on an edge of the volume and double-click volume_2 to create particle tracks through the volume.

To color the particle tracks by pressure coefficient, drag and drop the Scalar Fields->Pressure Coefficient tool onto an edge of the inlet. Select the inlet face in the Select dialog, click OK, and select Color Map to color the particle tracks. To rotate the view, left-click-and-drag the mouse in the View Window.

The pressure coefficient is a dimensionless number that represents pressure.

To change the style of the particle tracks, make sure that you have the inlet face selected in the View Window. Then go to the Properties panel and expand the Particles property (click on the + symbol to the left of Particles) to access the particle properties. Next to Type, select Tube to display the particle tracks as tubes instead of curves.

Try For Yourself

The sym project file for this tutorial can be viewed in SymLab or you can investigate this case yourself using our Panel Flow add-on.

The most convenient way to view and edit this case is to use our Professional add-on that combines all the add-ons used during this tutorial.