Learning Forum

[anuragpme17]

I am working on squeeze film damper (SFD) and trying to find the damping coefficient of the SFD. I am trying with solid model, so do i get any help in this.  

[peteroznewman]

Please reply with images inserted into your reply that show the geometry of the device with arrows and annotations that point to the squeeze film area, the larger volume of fluid adjacent to the squeeze film area, the material specs, the support boundary conditions and the loads applied.

[anuragpme17]

I want to find damping coefficient generated by the fluid film between parallel plates. I am looking for coupled analysis (structural and Fluid). Element type i have mentioned in image.

 

Thanks

Peteroznewman for your reply

[peteroznewman]

Just to clarify, you have a large flat fixed surface that has a uniform fluid film of depth d and you have a rectangular face in contact with that fluid film that is going to push down on the fluid film with a static load.

You say you are interested in a damping coefficient, but all you have is a static load, so the motion will just be an exponential decay, as there is no oscillatory component. If you create a 2-way FSI transient model, you can simulate directly the motion of the moving structure. 

• For the moving structure, what is the mass and the dimensions of the face in contact with the fluid?


• For the fluid, what is the density, viscosity, and any other important fluid properties (surface tension?)


• What is the magnitude of the load (or is the load caused by gravity acting on the mass of the moving structure)?

[anuragpme17]

Thanks peteroznewman

 

• Dimension of moving structure is 100mm x 30mm x 3mm


• Fluid properties are: Viscosity = 0.009 Pa.s, Density = 865 kg/m^3


• Magnitude of load is 10N. We are not considering gravity load

 

[peteroznewman]

Damping coefficient, c, is multiplied by the velocity to get the force, right?

c.v = f

So if you do the 2-way FSI and solve for the motion, you will get the velocity, then c = f / v.

You will find that the velocity is a function of the film thickness, d, therefore so is the damping coefficient.

Are you going to build the 2-way FSI to solve for the velocity and film thickness as a function of time?

[anuragpme17]

• Are you going to build the 2-way FSI to solve for the velocity and film thickness as a function of time?

Yes. 

Can please send me some link for 2-way FSI problem, for my help.

 

Thanks for your continuous and early reply

[anuragpme17]

Can someone help in resolving the above mentioned error. 

This is a 2-way FSI problem of Squeeze Film Damping on flat parallel plate. 

[peteroznewman]

Are you on a Student license or a Research license?

You can't do 2-way FSI on a Student license.

[anuragpme17]

I am having a research license. 

[peteroznewman]

You will have to do a lot of research to figure out how to do a successful 2-way FSI.

Discussion 1

Discussion 2

Discussion 3

YouTube Videos

https://www.youtube.com/watch?v=o8NDsAcfThQ

 

https://www.youtube.com/watch?v=oOGkvrnKS-c

[anuragpme17]

Thanks a lot Peteroznewman. 

 

I am very very thankful for your continuous reply. 

 

I have tried this video for resolving the problem but still I am unable to resolve it. 

Again i will try this video carefully.  

[anuragpme17]

I have tried the video related to this and applied the boundary condition and all according to this problem. After that I am getting the above mentioned error. 

Do any help me.

Thanks in advance.

[anuragpme17]

https://www.youtube.com/watch?v=gxdvROH_YcE

 

Hi, I am also using same problem to learn 2-way coupled problem. I have given all the conditions as is in video. But while solving coupled system, I am getting error " update failed for solution component in system coupling. The coupled update for system transient structural threw an exception. Error updating a cell solution in transient structural. View the messages in mechanical editor for more detail". In mechanical editor I have got the message " The shared license is not available to write the file". I am using workbench with Research license. Can you please tell me what may be the probable reason of this error.

[anuragpme17]

In transient solution information I am getting the message "MAPDL is unable to connect to the system coupling service on 0.0.0.0 through port 50293.  Please check ANSYS execution options -schost and  -scport for a System Coupling analysis and ensure that the host name    and the port number are correct". 

Any help will be beneficial for me. 

[FAHIME99]

In transient solution information I am getting the message "MAPDL is unable to connect to the system coupling service on 0.0.0.0 through port 50293.  Please check ANSYS execution options -schost and  -scport for a System Coupling analysis and ensure that the host name    and the port number are correct". 

Any help will be beneficial for me. 

I have same problem about of host name, can any body help me?

Thanks in advance.

[peteroznewman]

@FAHIME99, Are you on a Student license or a Research license? You can't do 2-way FSI on a Student license.

[FAHIME99]

 I am having a research license.

[peteroznewman]

I can't help with this question.

[FAHIME99]

OK,Thanks for your reply .

 

[anuragpme17]

@FAHIME99, this problem occurs some time due to antivirus installed in your system. So if you have installed antivirus in your system then remove it. this may work.

[Frederico Ricca]

Hi, I'm a student working on my thesis. My job is to develop a numeric tool to simulate the squeeze flow of an adhesive, similar to the initial problem on this page. Does anyone knows if it is possible to do this simulation without FSI? (Regarding only the fluid deformation and thickness variation). The velocity of the moving upper wall causing the fluid motion would be 0.1 mm/s and the inital thickness 2 mm. The objetive is to evaluate the flow once untill thickness = 1mm. 

[Rob]

If it's just the fluid, yes, you can use moving mesh in Fluent to squeeze the domain. FSI is only needed if the film will deform the metal bits too. Read up on the VOF model as well as moving deforming mesh. Please start a new Topic for any questions.