Flow Simulation(2)

Intro

SOLIDWORKS Flow Simulation

SOLIDWORKS® Flow Simulation is an intuitive Computational Fluid Dynamics (CFD) solution embedded within SOLIDWORKS 3D CAD that enables you to quickly and easily simulate liquid and gas flows through and around your designs to calculate product performance and capabilities.

SOLIDWORKS Flow Simulation is a general parametric flow simulation tool that uses the Finite Volume Method (FVM) to calculate product performance through “what if” studies that allow you to perform optimization using the results.

• https://www.solidworks.com/sw/docs/flow_sim_studentwb_2011_eng.pdf

Create differential drive robot assembly

• See Diff Drive Robot CAD (Note: the assembly may be referred to as “cube”)

Create wind tunnel

• Create new part → create sketch on right plane → Use center rectangle tool to draw a 25” x 25” shape.

• Extrude
  • Click Exit sketch → Features → Extruded Boss/Base → Rotate to face right
  • Set 36” long, extend from Mid Plane

• Use Shell tool to take out the left and right sides

• Save part as wind_tunnel.SLDPRT

Add cube to wind tunnel

• Create new assembly

• Add cube

  • Click insert components → select cube and wind tunnel parts

• rotate cube

• Click mate and select bottom face of wind tunnel and bottom side of cube

• Right click on tunnel and click Fix to lock it in place

• save assembly

Create Flow Simulation

Enable flow simulation add-in

• Click tools → Add-ins → check flow simulation

Flow Simulation Wizard

• Go to Tools → Flow Simulation → Project → Wizard → Project name: “wind tunnel”

• Change Velocity to mile/h

  

• Enable Fluid Flow and select Air (Gases) as default fluid

• Close off the tunnel
  • Click Flow Simulation tab → tools → Create Lids → Click on edges where lids will be placed

• Right click one side of wind tunnel and click Change transparency to hide

• Click Goals → Set Global Goals (helps with convergence of testing and meshing)
  • Check the following rows:
    • Velocity
    • Turbulence Intensity
    • Force
    • Force (X), Force (Y), Force (Z)

Set boundary conditions

• Set boundary condition
  • Click the inner side of the right lid
  • Select Inlet Velocity (steady airflow into the tunnel) and set it to 20 m/s
  • Set reference axis as x

• Set boundary conditions for back lid- Outlet (Pressure Open Condition) to allow air to escape naturally
  • Click left lid
  • Switch Pressure Opening → Select Environment Pressure

Run simulation

• Click Run → New Calculation to run simulation (When viewing results just click continue)

• View results box

• Click Insert Goals Plot and check Name

Run Visualizations

• Click Results → Flow Trajectories → Insert
  • Click Cube from assembly, set appearance to Lines (2) and select velocity

• You should now see a colored chart with mph and see how the windd is interacting and changing speed as it interacts with the cube.

• Insert Surface Plot
  • Hide the Flow Trajectories
  • Contours: Velocity, 25 levels
  • Vectors: Static vectors, velocity

• Showing both flow trajectories and surface plot