1. Create Case
We will start the simulation by creating a new case named propeller
Go to New panel
Provide name propeller
Click Create Case
2. Import Geometry - Propeller
After creating case Download Geometry: Propeller
Click Import Geometry
Select geometry file propeller.stl.gz
Click Open
3. Imported Geometry Units
The STL format does not contain the unit information which are defined during the geometry export. If we do not know the exported unit, we can estimate it based on the total size of the model. It is displayed next to Geometry size label. In our case, the default unit meter is correct.
To confirm default unit meter, press OK
4. Propeller Geometry
After importing geometry, it will appear in the 3D window.
Click Fit View to zoom the geometry
5. Domain Boundary
We need to create a cylindrical boundary for the domain. For this purpose, we will create a cylindrical geometry for later use in the meshing process.
Click Create Cylinder
Rename cylinder_1 to external
(double click on the name to rename it, press enter to apply)Click Properties button if properties panel is not displayed
Set origin, axis, and length of the cylinder accordingly
Origin \({\sf [m]}\)-1e-0300
Axis \({\sf [-]}\)100
Length \({\sf [m]}\)1.502
6. Refinement Area (I)
To better resolve the flow near the propeller, we will create an area with a higher mesh resolution. To do this, we will create a new geometry by copying settings from external geometry.
Click Options of the external geometry
Select Duplicate option
7. Refinement Area (II)
Click Properties if they are not displayed
Rename external_1 to refine
Set radius of the refinement geometry
Radius \({\sf [m]}\)0.3
8. Display Geometries
In order to see all geometries, we will decrease the opacity of the external and refine.
Select external
Click Display Properties
Adjust Opacity to 50%
Adjust opacity to 50% for refine geometry by repeating previous steps
9. Meshing Parameters - External
Go to Hex Meshing panel
Enable Mesh Geometry on external geometry
10. Meshing Parameters - Propeller
Select propeller geometry
Enable Mesh Geometry
Enable Create Boundary Layer Mesh
Set Refinement to Min 3 Max 4
11. Meshing Parameters - Refine
We want to create refinement in the area along the propeller induced flow.
Select refine geometry
Enable Mesh Geometry
Set refinement Level to 2
12. Base Mesh
We want to create a mesh of only one blade of the propeller. For this purpose, we will create a base mesh covering only one-fourth of the geometry.
Go to the Base tab
Define base mesh minimum and maximum extend
Min \({\sf [m]}\)000
Max \({\sf [m]}\)1.511Define Division along each axis
Division302020
13. Base Mesh Boundaries
2 Define boundary names accordingly
X- inlet
X+ outlet
Y- right_Z-_ _left_
14. Material Point
Now we will define material point outside the propeller geometry.
Go to Point tab
Set location of the material point
Material Point0.50.50.5
15. Start Meshing Process
Go to Mesh tab
Start the meshing process with Mesh button
16. Mesh
After a few minutes of meshing the following mesh should appear.
17. Boundary Types
After creating the mesh, we have to set proper boundary types.
Go to Mesh panel
Change the boundary type of the external geometry to patch
Make sure you have appropriate boundary types selected
18. Boundary Interface (I)
As we will be simulating only one blade of the propeller we have to create a boundary interface to make the model periodic.
Hold CTRL key and select left and right boundary
Click Create Arbitrary Interface between left and right boundary
19. Boundary Interface (II)
Expand the interface properties
Change Transform type to Rotational
Define Rotation Axis
Rotation Axis100
20. Select Solver - SIMPLE
For the simulation of a marine propeller, we will use a steady-state incompressible simpleFoam solver.
Go to Setup panel
Enable Steady State filter
Enable Incompressible flow filter
Pick SIMPLE (simpleFoam) solver
Click Select button to choose the solver
21. Turbulence Model
For the purpose of this tutorial we will simulate the turbulence phenomenon using \(Realizable \; k{-} \varepsilon\) model.
Go to Turbulence panel
Select RANS modeling
Select \(Realizable \; k{-} \varepsilon\) turbulence model
22. Water Properties
Go to Transport Properties panel
Define kinematic viscosity of water
\(\nu\) \({\sf [m^2/s]}\)1e-06
Note that you do not have to define density. The equations that describe single phase incompressible flow operates on a kinematic pressure(pressure divided by reference density). Therefore, the density property does not explicitly appear and you have to remember to multiply resulting pressure and forces by the density value to obtain a physical results.
23. Cell Zones for MRF (I)
To be able to model propeller rotation, we will take advantage of a rotating reference frame. This technique will allow modeling the propeller rotation without a need to rotate the mesh. The rotating reference frame can only be applied to a sub-region of the mesh defined by a cell zone object (a list of mesh cells). Therefore, we will first create a cell zone.
Go to Mesh panel
Expand list of options form the default region
Select Add Cell Zones from the menu
24. Cell Zones for MRF (II)
For the purpose of this tutorial we will use the whole mesh as the rotating zone. To do this we need to create the cell zone inside the external geometry.
Select external geometry
Click Create Cell Zones
25. Rotating Reference Frame
Go to Cell Zones panel
Enable Rotating Reference Frame for external zone
Define Axis of the propeller
Axis-100Select boundaries that will not be defined in the rotating frame of reference
Static Boundaries:
external
inlet
left
outlet
right
26. Boundary Conditions - External (Turbulence)
Go to Boundary Conditions panel
Select external boundary
Select Turbulence tab
Set Turbulence Intensity to 1e-02
27. Boundary Conditions - Inlet
We will use the same boundary conditions for inlet and external boundaries, to achieve this we can copy settings from the external boundary to inlet.
Make sure you have selected the external boundary
Click Copy Boundary Conditions
Select inlet boundary
Click Copy
28. Boundary Conditions - Outlet
Change outlet character to Outflow
29. Monitor Forces
We want to monitor solution progress by observing force coefficients.
Go to Monitors panel
Select Forces tab
Expand Monitored Boundaries list
Select propeller boundary
30. Run - Time Control
Go to Run panel
Set Number of Iterations to 1000
31. Run - CPU
To speed up the calculation process increase the number of CPUs basing on your PC capability. The free version allows you to use only 2 processors in parallel mode. To get the full version, you can use the contact form to Request 30-day Trial
Estimated computation time for 2 processors: 10 minutes
Switch to CPU tab
Use parallel mode
Increase the Number of processors
Click Run Simulation button
32. Monitor Solution - Force
Check if solution converges by observing stabilization of forces on the propeller boundary.
Click on Forces tab to display Force Monitor
33. Calculate Additional Fields
When a simulation is finished, we want to calculate additional solution field to be used in postprocessing.
Go to Calculate panel
Select Q Criterion field
Calculate the field
Please Note: After clicking the Calculate button, SimFlow will calculate the new flow variable, which will be stored in your project folder and will be accessible in the ParaView.
34. Start Postprocessing with ParaView
Go to Postprocessing panel
Run ParaView
35. ParaView - Load Results
Now we are loading results into the ParaView
Click Last Frame to select the last result set
Click Apply to load results into ParaView
After loading results they will be shown in the 3D graphic window
36. ParaView - Display Q Contour (I)
To show the propeller we will create now a contour.
Make sure you have your case selected
Click Contour
37. ParaView - Display Q Contour (II)
Set Contour by to Q
Set contour range to ` 500 ` and click enter
(double click to edit visible value)Click Apply to create new contour
After applying changes the contour will be shown in the 3D window
38. ParaView - Show Full Propeller (I)
As you can see there is only a quarter of the propeller visible and we would like to show the full geometry. In order to do that we have to duplicate and transform a partial propeller.
Make sure you have Contour1 selected
From the Sources Menu select Search option to open a search window
Start typing the word transform
Select Transform option
Make sure you have Transform1 selected
Define 90 degree rotation about the X axis and click enter
Click Apply 2 times to create transformation
39. ParaView - Show Full Propeller (II)
We have to repeat the previous step to make another transformation - Transorm1 → Transform2
Make sure you have Transform1 selected
From the Sources Menu select Search option to open a search window
Start typing the word transform
Select Transform option
Make sure you have Transform2 selected
Define 90 degree rotation about the X axis and click enter
Click Apply 2 times to create transformation
40. ParaView - Show Full Propeller (III)
We have to repeat the previous step to make another transformation - Transorm2 → Transform3
Make sure you have Transform2 selected
From the Sources Menu select Search option to open a search window
Start typing the word transform
Select Transform option
Make sure you have Transform3 selected
Define 90 degree rotation about the X axis and click enter
Click Apply 2 times to create transformation
41. Display Full Propeller
To make the full geometry visible, we have to change the visibility of all geometries
Make sure the contour and all its transformations are visible
Select Contour1
Choose pressure p from the coloring list
Click Toggle Color Legend Visibility and choose Blue to Red Rainbow
42. Final Results
In the 3D view the contour of full propeller should appear
