Marine Propeller


1. Create Case

We will start the simulation by creating a new case named propeller

1. Go to New panel
2. Provide chosen name propeller
3. Click Create Case

2. Import Geometry

After creating case Download Geometry: propeller.stl.gz

1. Click Import Geometry
2. Select geometry file propeller.stl.gz
3. Click Open

3. Propeller Geometry

After importing geometry, it will appear in the 3D window.

1. Click Fit View to zoom the geometry

4. 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.

1. Click Create Cylinder
2. Rename cylinder_1 to external
(double click on the name to rename it, press enter to apply)
3. Click Properties button if properties panel is not displayed
4. Set origin, axis, and length of the cylinder accordingly

Origin[m] -1e-03 0 0
Axis[-] 1 0 0
Length[m] 1.502

5. 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.

1. Click Options of the external geometry
2. Select Duplicate option

6. Refinement Area (II)

1. Click Properties if they are not displayed
2. Rename external_1 to refine
3. Set radius of the refinement geometry

Radius[m] 0.3

7. Geometries

In order to see all geometries, we will decrease the opacity of the external and refine.

1. Select external
2. Click Display Properties
3. Adjust Opacity to 50%
4. Adjust opacity to 50% for refine geometry by repeating previous steps

8. Meshing Parameters - External

1. Go to Hex Meshing panel
2. Enable meshing on external geometry

9. Meshing Parameters - Propeller

1. Select propeller geometry
2. Enable meshing on propeller geometry
3. Enable boundary layers
4. Set minimum and maximum mesh refinement

Min 3 Max 4

10. Meshing Parameters - Refine

We want to create refinement in the area along the propeller induced flow.

1. Select refine geometry
2. Enable meshing on refinement geometry
3. Set refinement Level to 2

11. 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.

1. Go to the Base tab
2. Define base mesh minimum and maximum extend

Min[m] 0 0 0
Max[m] 1.5 1 1

3. Define Division along each axis

Division 30 20 20

12. Base Mesh Boundaries

1, 2. Define boundary names accordingly

X- inlet
X+ outlet
Y- right

Z- left

13. Material Point

Now we will define material point outside the propeller geometry.

1. Go to Point tab
2. Set location of the material point

Material Point 0.5 0.5 0.5

14. Start Meshing Process

1. Go to Mesh tab
2. Start the meshing process with Mesh button

15. The Mesh

After a few minutes of meshing the following mesh should appear.

16. Boundary Types

After creating the mesh, we have to set proper boundary types.

1. Go to Mesh panel
2. Change the boundary type of the external geometry to patch
3. Make sure you have appropriate boundary types selected

17. 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.

1. Hold Ctrl key and select left and right boundary
2. Click Create Arbitrary Interface between left and right boundary

18. Boundary Interface (II)

1. Expand the interface properties
2. Change Transform type to Rotational
3. Define Rotation Axis

Rotation Axis 1 0 0

19. Select Solver

For the simulation of a marine propeller, we will use a steady-state incompressible simpleFoam solver.

1. Go to Setup panel
2. Enable Steady State filter
3. Enable Incompressible flow filter
4. Pick SIMPLE (simpleFoam) solver
5. Click Select button to choose the solver

20. Turbulence Model

For the purpose of this tutorial we will simulate the turbulence phenomenon using Realizable k-ε model.

1. Go to Turbulence panel
2. Select RANS modeling
3. Select Realizable k-ε turbulence model

21. Water Properties

1. Go to Transport Properties panel
2. Define kinematic viscosity of water

v[m2/s] 1e-06

Note that you do not have to define density. Te 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.

22. 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.

1. Go to Mesh panel
2. Expand list of options form the default region
3. Select Add Cell Zones from the menu

23. 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.

1. Select external geometry
2. Click Create Cell Zones

24. Rotating Reference Frame

1. Go to Cell Zones panel
2. Enable Rotating Reference Frame for external zone
3. Define Axis of the propeller

Axis -1 0 0

4. Select boundaries that will not be defined in the rotating frame of reference

Static Boundaries external inlet left outlet right

25. Boundary Conditions – External (Turbulence)

1. Go to Boundary Conditions panel
2. Select external boundary
3, Select Turbulence tab
4. Set Turbulence Intensity to 1e-02

26. 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.

1. Make sure you have selected the external boundary
2. Click Copy Boundary Conditions
3. Select inlet boundary to copy to
4. Click Copy

27. Boundary Conditions – Outlet

1. Change outlet character to outflow

28. Monitor Forces

We want to monitor solution progress by observing force coefficients.

1. Go to Monitors panel
2. Select Forces tab
3. Expand Monitored Boundaries list
4. Select propeller boundary

29. Run Simulation

1. Go to Run panel
2. Set Number of Iterations to 1000
3. Click Run Simulation

30. Monitor Solution - Force

Check if solution converges by observing stabilization of forces on the propeller boundary.

1. Click on Forces tab to display Force Monitor

31. Calculate Additional Fields

When a simulation is finished, we want to calculate additional solution field to be used in postprocessing.

1. Go to Calculate panel
2. Select Q Criterion field
3. 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.

32. Start Postprocessing with ParaView

1. Go to Postprocessing panel
2. Run ParaView

33. ParaView - Load Results

Now we are loading results into the ParaView

1. Click Last Frame to select the last result set
2. Click Apply to load results into ParaView
3. After loading results they will be shown in the 3D graphic window

34. ParaView - Display Q Contour (I)

To show the propeller we will create now a contour.

1. Make sure you have your case selected
2. Click Contour

35. ParaView - Display Q Contour (II)

1. Set Contour by to Q
2. Set contour range to 500 and click enter
(double click to edit visible value)
3. Click Apply to create new contour
4. After applying changes the contour will be shown in the 3D window

36. 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.

1. Make sure you have Contour1 selected
2. From the Sources Menu select Search option to open a search window
3. Start typing the word transform
4. Select Transform option
5. Make sure you have Transform1 selected
6. Define 90 degree rotation about the X axis and click enter
7. Click Apply 2 times to create transformation

37. ParaView - Show Full Propeller (II)

We have to repeat the previous step to make another transformation – Transorm1 -> Transform2

1. Make sure you have Transform1 selected
2. From the Sources Menu select Search option to open a search window
3. Start typing the word transform
4. Select Transform option
5. Make sure you have Transform2 selected
6. Define 90 degree rotation about the X axis and click enter
7. Click Apply 2 times to create transformation

38. ParaView - Show Full Propeller (III)

We have to repeat the previous step to make another transformation – Transorm2 -> Transform3

1. Make sure you have Transform2 selected
2. From the Sources Menu select Search option to open a search window
3. Start typing the word transform
4. Select Transform option
5. Make sure you have Transform3 selected
6. Define 90 degree rotation about the X axis and click enter
7. Click Apply 2 times to create transformation

39. Show Full Propeller (IV)

To make the full geometry visible, we have to change visibility of all geometries

1. Make sure the contour and all its transformations are visible

40. Contour

In the 3D view the contour of full propeller should appear

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