Fluid viscous damping coefficients

[simulation_engineer_2022]

Hi everyone!

Could you please help me understand the proper way of calculating viscous damping coefficients for a set of frequencies? The core of the design consists of a cylinder filled with a viscous fluid, one side of which is subjected to excitation at a given frequency. For now I have no clue where to start a research and I do have several basic questions:

1) Is it solvable by means of FEA? What material properties should be known and what procedure should be used?

2) Maybe it should be solved using CFD methods?

3) Or maybe FSI is the method one should use? The design also contains several components with rubber parts, springs and etc.

4) Maybe calculating these coefficients makes no sense and the only right way is to conduct a physical experiment? In this case what conceptually should be the experimental setup?

Please redirect me to a specific thread if something similar already exists or give me some articles to investigate. Thanks in advance!

 

[FEA way]

Assuming that the cylinder is only partially filled with a fluid, this sounds similar to sloshing simulations. They can be performed using Abaqus/Explicit and specialized techniques such as ALE adaptive meshing for small-amplitude sloshing and SPH or CEL for large-amplitude sloshing.

 

[simulation_engineer_2022]

Hi, FEA way! Thanks for the response!

I probably should have described it earlier, my bad, but the main principle of this device is to damp oscillations by conversion the kinetic energy of cylinder metal parts motion into thermal energy of the liquid. Does Abaqus/Explicit procedure with ALE / SPH / CEL techniques consider this?

How could one output damping coefficients for these types of simulation? What liquid properties are crucial?

 

[FEA way]

Yes, it should be possible. At least with CEL and dynamic explicit temperature-displacement procedure. But it might be difficult to model due to the complexity of the problem.

When it comes to damping coefficients, you should look for the approaches used to determine them experimentally and try to transfer those approaches to simulations. There are some research papers that may help.