Geometry Generation

Introduction

OpenVSP is a parametric aircraft geometry tool. It allows the user to quickly generate aircraft geometries. We will use it to generate the ONERA M6 wing. This is not a full blown tutorial, more a walk through. If you want to learn more about it, you can go to their tutorial videos

Files

Navigate to the directory overset/geo in your tutorial folder. Copy the file profile_m6.dat from the tutorial folder.

$ cp tutorial/overset/geo/profile_m6.dat .

Geometry Overview

Before we start, we should familiarize ourself with the geometry we are going to create. The real ONERA M6 experiment looked like this:

../_images/overset_view-of-ONERA.jpg

ONERA M6 experiment [O1].

As we are not the first to simulate this wing, we can grab the geometry data and the airfoil from [O2]. Here is a short summary:

Airfoil

profile_M6 (this can also be found in the tutorial folder)

Root Chord

0.8105 m

Tip chord

0.4559 m

Semispan

1.1963 m

Leading Edge Sweep

30°

Geometry Generation

OpenVSP Window

If you open OpenVSP the first time, it should look like that:

../_images/overset_vsp_overview.png

OpenVSP Overview.

Lets start the geometry generation:

Add a new Wing

  1. Choose WING

  2. Click Add

  3. A new Window Wing: WingGeom pops up

../_images/overset_vsp_add_wing.png

Add a new wing to OpenVSP.

We notice a new geometry in the Main View. This is the wing we just added. It also shows up as WingGeom in the Geom Browser. To control the view, use the following key- and mouse combinations:

zoom

Press the middle mouse button and move your mouse up and down.

rotate

Press the left mouse button and move your mouse.

move

Press the right mouse button and move you mouse.

Manipulate the wing geometry

Move your view, so you can take a look the whole wing. The first thing we notice, it is a ‘full’ wing, but we need only half of it. To change this, do the following:

  1. Click on XForm

  2. Uncheck XZ in the Symmetry area

../_images/overset_vsp_half_wing.png

Disable XZ Symmetry.

Now we change the wing geometry. OpenVSP has no units, but we want to create the mesh in meters and thus choose our unit size to be one meter.

  1. Click on Sect

  2. Change the values to the values listed in the table above

../_images/overset_vsp_wing_geo.png

Adjust the wing geometry.

To make the meshing process easier, we will round the tip:

  1. Click on Plan

  2. Choose Round for the Tip Cap Type

../_images/overset_vsp_round_tip.png

Adjust the wing geometry.

Change the airfoil

Now, the wing geometry is as it should be, but we still have to change the airfoil:

  1. Click on Airfoil

  2. Select AF_FILE for Choose Type

  3. Open the file profile_m6.dat in the tutorial\overset\geo folder

  4. Click on the right single arrow to select the Tip airfoil

  5. repeat the process from 2 to 3

../_images/overset_vsp_change_airfoil.png

Change the airfoil.

Export the geometry

Now we can export the geometry to read it into our meshing software. It might also be a good idea to save it first.

  1. Click on File -> Export

  2. Click Untrimmed IGES (.igs)

  3. Choose the proper unit. In this case it should be meter

  4. Click OK and save it

../_images/overset_vsp_export.png

Export the geometry.