For Validation

dthakur · October 9, 2024, 13:28

I need to validate one case and i am having problem to set up a given equation . like in which openfoam file i can find nonlinear damping and cubic term. i am using simpletic solver for my case related to flow induced heaving and pitching any idea or help would be really appreciated.

CFD_with_Skill-Lync · October 10, 2024, 07:12

Can you explain the physics a little bit? It would help in narrowing down the terms you would need to focus on.

Also, please mention the OpenFOAM version you are using.

Regards

Team Skill-Lync

dthakur · October 10, 2024, 10:22

I'm working on validating a NACA 0012 airfoil and need to simulate flow-induced heaving and pitching. The equations in my reference paper include both linear and non-linear terms. My question is where to implement the non-linear terms in OpenFOAM. I understand that the 6DOF solid body framework has solvers and folders for constraints and restraints. In my case, I have a linear and angular spring with no damper, but the equations include non-linear terms in the stiffness (K) component. Where should I incorporate these non-linear and coupling terms?

CFD_with_Skill-Lync · October 14, 2024, 04:28

The 6DOF solver can take a text file input with time vs location. If you are interested, you could give the motion of your airfoil as a tabulated input to your dynamicMeshDict file.

Instead, OpenFOAM foundation uses #calc function where you can directly input your motion with respect to time, while defining the X, Y and Z coordinates of your object.

If you want to incorporate the equations for motion of your object, these are two ways in which you could do it. I would advise start with the tabulated 6DOF, it's relatively easier as all it would take you is a simple Python script to write the text file.

dthakur · October 14, 2024, 11:16

can you share more details how to put #calc in dynamicMeshDictFile. my equations has non linear terms as well and i have to find pitching and heaving motion. equations are attached

dthakur · October 25, 2024, 14:54

In my study of vortex-induced vibrations (VIV) for a vibrating cylinder, I have a mass ratio m* is 10 Re = 100 and Ur* from 4 to 8. I am trying to determine which parameters to adjust in order to achieve different amplitudes of vibration for the cylinder at these various reduced velocities. However, I am encountering an issue where I observe the same amplitude at each reduced velocity, regardless of the changes I make. Can someone explain why this might be happening? I appreciate any insights, as I am conducting this analysis using OpenFOAM.

October 10, 2024, 07:12	Bit more background needed	#2
CFD_with_Skill-Lync New Member Skill-Lync CFD Join Date: Sep 2024 Location: Chennai Posts: 21 Rep Power: 2	Can you explain the physics a little bit? It would help in narrowing down the terms you would need to focus on. Also, please mention the OpenFOAM version you are using. Regards Team Skill-Lync

October 10, 2024, 10:22		#3
dthakur New Member Dilip Join Date: Sep 2024 Posts: 8 Rep Power: 2	I'm working on validating a NACA 0012 airfoil and need to simulate flow-induced heaving and pitching. The equations in my reference paper include both linear and non-linear terms. My question is where to implement the non-linear terms in OpenFOAM. I understand that the 6DOF solid body framework has solvers and folders for constraints and restraints. In my case, I have a linear and angular spring with no damper, but the equations include non-linear terms in the stiffness (K) component. Where should I incorporate these non-linear and coupling terms?

October 14, 2024, 04:28		#4
CFD_with_Skill-Lync New Member Skill-Lync CFD Join Date: Sep 2024 Location: Chennai Posts: 21 Rep Power: 2	The 6DOF solver can take a text file input with time vs location. If you are interested, you could give the motion of your airfoil as a tabulated input to your dynamicMeshDict file. Instead, OpenFOAM foundation uses #calc function where you can directly input your motion with respect to time, while defining the X, Y and Z coordinates of your object. If you want to incorporate the equations for motion of your object, these are two ways in which you could do it. I would advise start with the tabulated 6DOF, it's relatively easier as all it would take you is a simple Python script to write the text file.

October 25, 2024, 14:54		#6
dthakur New Member Dilip Join Date: Sep 2024 Posts: 8 Rep Power: 2	In my study of vortex-induced vibrations (VIV) for a vibrating cylinder, I have a mass ratio m* is 10 Re = 100 and Ur* from 4 to 8. I am trying to determine which parameters to adjust in order to achieve different amplitudes of vibration for the cylinder at these various reduced velocities. However, I am encountering an issue where I observe the same amplitude at each reduced velocity, regardless of the changes I make. Can someone explain why this might be happening? I appreciate any insights, as I am conducting this analysis using OpenFOAM.