Thank you sebastiano. I would like to say to you and your followers, something that i have learned in my case. If you are dealing with dynamic mesh, check your mesh, check it again and again. If your mesh is not properly generated, Cyclic AMI is not going to work. I have lost 3 days for it. Check mesh.
yes, check mesh is very important if you need your solution to be accurate (always apart from tutorials), and usually the -allGeometry -allTopology options highlight some warning that you would miss with a normal call to checkMesh. Mesh quality is strictly coupled with the choiche of the numerical scheme in the system/fvSchemes
"Thank you for your insights. I have a question regarding airfoil simulations. I'd like to add two jets on the surface of the airfoil. How should I combine the boundary conditions for the jets and dynamic mesh? Or do you have any better suggestions?"
Hi, I want to create a sliding interface for a wind turbine, and then when the turbine is rotating I want to put this in another cylinder and rotate-oscilate it. so it will be like a turbine rotating and pitching simultaneously. can you please guide me and if possible make a tutorial for it. Thank you
Hi! First of all, I'd like to thank you for this wonderful tutorial. Now, the reason I'm commenting is that I'm unable to get past the createPatch step in this tutorial. I'm facing an error when I run createPatch. The error is - none is not in enumeration: 5 ( coincidentFullMatch NoOrdering rotational translational unknown ) Can you please help me understand as to what I must do? Thanks in advance.
Try commenting that line (transform none) in both patches creation. That parameter is not necessary in this tutorial. It is strange because it should work with transform none, even if it is not on the available options. Are you using OpenFOAM-8?
If my airfoil is deforming not in rigid body motion, which approach should I use? The displacmentLaplacian and SBRStress solver cannot handle large mesh motion. Is it possible to use AMI to confine the mesh motion around the deforming airfoil? Thank you!
OpenFOAM can't handle that kind of motion by default. You can use something similar to the SLERP interpolation, which is at the base of the InterpolatingSolidBody motion (th-cam.com/video/UUla8AayM8Y/w-d-xo.html).
Firstly, thank you for your video, it helped me to understand the approach. I want to ask if it is possible to define two rotating different regions, which are rotating with different omega, in dynamicMeshDict?
As Malhar says, you can define more than 2 regions and use the multi motion to specify the motion in each region. It is not a easy task since most of the time you have to use a tabulated motion, which means that you have to write down the body motion time history. Keep in mind that the motion is displacement (deltaX), not the actual coordinates of the CG of the body you want to move.
First of all, thank you for all this videos. It's such a great stuff in order to learn about the DynamicMesh in Openfoam. Second, I would like to ask you something regarding force coefficents. I want to calculate the cl and cd of the airfoil for every timestep using the forcecoeffs function from OpenFoam. However, I need the angle of attack for every timestep to set the lift dir and the drag dir (don't hesitate to correct me if I am wrong or there is another easier way to perform it) and eventually calculate the cl and cd. So.. how can I get these angles for every timestep? How have you calculated the cl and cd ? Thanks in advance and greetings from Spain!!
Thank u for ur video, i do have one question how to use searchableCylinder? suppose i have a 2D surface of 15x15 dimension and i have rectangular whole at the center of the domain. i want to make a baffle cylinder of radius 2 for my rectangular whole. should i define point1 and point2 as (0 1e3 0) and (0 -1e3 0)? i saw UserGuide of openfoam for searchableCylinder, still couldn't get clarity on this
I don't know what your coordinate system is but anyway for OpenFOAM a geometry is just a geometry, it means that you can (and usually it is done) have it dafined also outside of the actual mesh. If you want to extract a portion of the mesh, or simply create a patch in the snappyHexMesh, you have to have your cyliner cutting the mesh entirely. So the big numbers that you usually see in the 2D tutorials refer to the direction normal to your 2D plane, whicn is theoretically infinite. Since OpenFOAM cannot handle 2D meshes (intended as surface meshes) for the flow solution, you will always have a certain thickness of your mesh, so in order to be sure that your geometry is passing from one side to the other one pople generally set a very high value in that direction. Was it clear?
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Thank you sebastiano. I would like to say to you and your followers, something that i have learned in my case. If you are dealing with dynamic mesh, check your mesh, check it again and again. If your mesh is not properly generated, Cyclic AMI is not going to work. I have lost 3 days for it. Check mesh.
yes, check mesh is very important if you need your solution to be accurate (always apart from tutorials), and usually the -allGeometry -allTopology options highlight some warning that you would miss with a normal call to checkMesh. Mesh quality is strictly coupled with the choiche of the numerical scheme in the system/fvSchemes
Wonderfully explained. Thank you!
thank you for the comment!
great! Thank you for sharing
"Thank you for your insights. I have a question regarding airfoil simulations. I'd like to add two jets on the surface of the airfoil. How should I combine the boundary conditions for the jets and dynamic mesh? Or do you have any better suggestions?"
What to do if I want the wing to move up and down as well along with rotating?
Hi, I want to create a sliding interface for a wind turbine, and then when the turbine is rotating I want to put this in another cylinder and rotate-oscilate it. so it will be like a turbine rotating and pitching simultaneously. can you please guide me and if possible make a tutorial for it. Thank you
Hi!
First of all, I'd like to thank you for this wonderful tutorial.
Now, the reason I'm commenting is that I'm unable to get past the createPatch step in this tutorial.
I'm facing an error when I run createPatch. The error is -
none is not in enumeration:
5
(
coincidentFullMatch
NoOrdering
rotational
translational
unknown
)
Can you please help me understand as to what I must do?
Thanks in advance.
Try commenting that line (transform none) in both patches creation. That parameter is not necessary in this tutorial. It is strange because it should work with
transform none, even if it is not on the available options. Are you using OpenFOAM-8?
If my airfoil is deforming not in rigid body motion, which approach should I use? The displacmentLaplacian and SBRStress solver cannot handle large mesh motion. Is it possible to use AMI to confine the mesh motion around the deforming airfoil? Thank you!
OpenFOAM can't handle that kind of motion by default. You can use something similar to the SLERP interpolation, which is at the base of the InterpolatingSolidBody motion (th-cam.com/video/UUla8AayM8Y/w-d-xo.html).
Firstly, thank you for your video, it helped me to understand the approach. I want to ask if it is possible to define two rotating different regions, which are rotating with different omega, in dynamicMeshDict?
I have the issue could you guide for the changes to be done in dynamics mesh directory.
Yes, it is possible, its called multiMotion, search for this keyword on Google, you will find it
As Malhar says, you can define more than 2 regions and use the multi motion to specify the motion in each region. It is not a easy task since most of the time you have to use a tabulated motion, which means that you have to write down the body motion time history. Keep in mind that the motion is displacement (deltaX), not the actual coordinates of the CG of the body you want to move.
Is it possible to do 3D transient simulation of rotating sphere using same procedure as discussed in this video?
First of all, thank you for all this videos. It's such a great stuff in order to learn about the DynamicMesh in Openfoam. Second, I would like to ask you something regarding force coefficents. I want to calculate the cl and cd of the airfoil for every timestep using the forcecoeffs function from OpenFoam. However, I need the angle of attack for every timestep to set the lift dir and the drag dir (don't hesitate to correct me if I am wrong or there is another easier way to perform it) and eventually calculate the cl and cd. So.. how can I get these angles for every timestep? How have you calculated the cl and cd ? Thanks in advance and greetings from Spain!!
The lift is by definition aligned with the incoming flow, so, as long as that remain constant, you should have that value from the beginning.
Thank u for ur video, i do have one question how to use searchableCylinder? suppose i have a 2D surface of 15x15 dimension and i have rectangular whole at the center of the domain. i want to make a baffle cylinder of radius 2 for my rectangular whole. should i define point1 and point2 as (0 1e3 0) and (0 -1e3 0)? i saw UserGuide of openfoam for searchableCylinder, still couldn't get clarity on this
I don't know what your coordinate system is but anyway for OpenFOAM a geometry is just a geometry, it means that you can (and usually it is done) have it dafined also outside of the actual mesh. If you want to extract a portion of the mesh, or simply create a patch in the snappyHexMesh, you have to have your cyliner cutting the mesh entirely. So the big numbers that you usually see in the 2D tutorials refer to the direction normal to your 2D plane, whicn is theoretically infinite. Since OpenFOAM cannot handle 2D meshes (intended as surface meshes) for the flow solution, you will always have a certain thickness of your mesh, so in order to be sure that your geometry is passing from one side to the other one pople generally set a very high value in that direction. Was it clear?