Creating geom.spj

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• create a directory for the .smf and .spj files (mkdir SMF_and_SPJ_files), cd to that directory and start SimulationMaker. There are a number of versions of simulation maker available. One of the oldest is 090321 which can be run with

 vglrun /usr/local/simapps/sdk-090321/simapps  SimulationMaker

At the time of writing, this version is commonly used, but very deprecated. Instead, try to use just about any other version we have, e.g.

 soft add +simappssdk-7.2-120125
 simapps SimulationMaker

• In the GUI which comes up
  • Set "Default Solver" to Phasta
  • Browse to the appropriate geometry file and select it (make sure it is not the SpaceClaim parasolid file; it should be the file you saved from ThreeDViewer - geom.xmt_txt) (Debated - it may be that the parasolid was saved in an unsupported version; try v24.0 instead of v25.0).
  • Turn OFF sliver feature suppression
  • Click Define Simulation Model Instance
• The attribute list and model will appear in split windows. At the top of the list, double click on the name "problem definition" and set the name to "geom".
• To set attributes, make sure the field with "geom", which you just changed, is selected. Using the model to the right, click on whichever faces you want to give attributes, and go to "Create" at the upper left hand corner to select the appropriate attribute.
• The names of the attributes are arbitrary, but should be something meaningful to the user and whoever else is involved in the project.
• Make sure you save the smf file very frequently so that you don't lose your work. Do File -> Save.

For Incompressible Flow

Inflow

comp3: The name is arbitrary but should be set to something meaningful (i.e. Inflow). Click on the inflow face (which is the face which makes up the front of the wind tunnel) and go to Create -> comp3. Set vector magnitude to the free-stream velocity you want. Set the vector direction to the direction (i.e. if the free-stream velocity moves strictly along the x-axis, the direction would be [1 0 0]). Even if the vector magnitude is 0, the direction CANNOT be [0 0 0]. This will cause Phasta to crash. It must have at least one non-zero component. In this case, just set it to [1 0 0].

scalar_1: Click on the inflow face and go to Create -> scalar_1. Set the field "Type: scalar_1" to 1.8e-7. This is the eddy viscosity at the inlet. (Debated: Spalart Almaras EV BCs typically use a value on the order of molecular viscosity which, in turn, is typically approximately 1.8e-5 for air at room temperature)

Outflow

natural pressure: Set "Type: natural pressure" to 0.

scalar_1 flux: Set this to 0.

traction vector: Set this to [0 0 0]

TopBottomWalls

• These are the walls of the wind tunnel that bound the model from above and below. The terms "above" and "below" are arbitrary, but we typically define them so that their normal points along the z-axis. However, this is not necessary.

scalar_1 flux: Set this to 0.

traction vector: Set this to [0 0 0].

comp1: The vector magnitude should be 0. The direction depends on which direction the normal of the wall points. If it is along the z-axis, then this will be [0 0 1]. If it is along the y-axis, this will be [0 1 0]. This attribute signifies a no-penetration condition through the tunnel walls.

SideWalls

• These are also arbitrary. But if you already defined the TopBottomWalls, then you already know which walls they are.

scalar_1 flux: Set this to 0

traction vector: Set this to [0 0 0]

comp1: Set vector magnitude to 0. The direction should be set to whichever direction the normal of the walls point.

Initial Conditions

Initial Velocity: In the model window, go to Selection -> Select Model. In the attribute window, go to Create -> initial velocity. Set this to [1e-8 0 0]

Initial Pressure: Set to 0

Initial Scalar_1: Set to 1.8e-7

No-Slip Walls

comp3: Set the no-slip walls with comp3. The name should be something meaningful (i.e. NoSlip_comp3). For Boeing, the the only walls that do not get no-slip are the tunnel walls. Therefore, what you should do is go to Selection -> "Select All Model Faces" and then create a comp3. The vector magnitude is 0, and the direction must be non-zero (i.e. [1 0 0] is fine but [0 0 0] is not). Click Apply and Close. Re-open that attribute, find each of the 6 tunnel walls and click on "Model Associations" at the top of the Attribute Editor and delete them. The faces should be in numerical order in the list. Apply and Close.

Setting Eddy Viscosity on the Wall

scalar_1: For the Boeing model, the only walls that don't get this attribute are the tunnel walls. Set this attribute to 0.

Computing Distance to the Wall for the Turbulence Model

turbulence wall: For the Boeing model, the only faces that do not receive this attribute are the tunnel walls and the jet diaphragms.

Identifying Specific Surfaces with an ID Number

• This must be done for the jet diaphragms in order to turn them on and off. The jets are traditionally ordered from tip to root. So if there are 12 jets, label the jet closest to the tip 1, and the jet closest to the root 12. Click on the surface, go to Create -> Surf ID. Set the value of the ID in Type: Surf ID.

• This also must be done in order for phasta to compute the aerodynamic force for sets of surfaces. If you want to know C_L for the rudder and stabilizer for example, give all the stabilizer surfaces an ID of 13, and all the rudder surfaces an ID of 14. The value of the ID is arbitrary, but must be different from other surf ID's.

Creating geom.spj

• When all the attributes are completed, save the smf file one last time. At the top menu, to the right of "Meshing Process", click on Attributes -> Export Attributes. Save it in the same place as geom.smf and save it as geom.spj.