General Mechanical

General Mechanical

Modal Acoustics

    • krishnendu
      Subscriber

      Hi,

      I am using Ansys Workbench 2021 R2 version for studying the mode shapes of a tube filled with water. In this case, both ends of the tube is closed and the tube is flexible (rubber material). Also, the damping is not considered for the water volume inside the tube. I could successfully run the modal acoustics and get the mode shapes. However, I haven’t included the FSI layer between the tube and the water volume. Please let me know if I can get the correct mode shapes without defining the FSI.

      In another simulation, I have added a contact region between the tube wall and the fluid medium and defined the FSI layer. Simulation was not successful with FSI. It will be great to get your views on this.

       Thank you in advance.

      Best,

      Krishna

    • peteroznewman
      Subscriber
    • krishnendu
      Subscriber
      Hi Peteroznewman Thank you very much for suggesting this link. It is very helpful.
      From the discussion, I understand that a coupled vibro-acoustic analysis can solve the fluid filled tube problems. However, my concern is if I donÔÇÖt provide the FSI in Ansys will the effect of water (acoustic) be considered on the elastic tube (structure)? How much importance is there in defining the FSI layer?Any suggestions on this will be a great help.
      Best Krishna
    • peteroznewman
      Subscriber
      I will let Erikanswer your question.
    • krishnendu
      Subscriber
      Hi Peteroznewman Thank you for tagging Erik to the earlier query, I am waiting to hear from him on earlier issue.
      I have another query on the modal mass values from Ansys simulation. It will be great to know your thoughts on this.
      Earlier, I have done a modal analysis on an elastic beam and the modal mass for each mode was displayed in solution output file. However, when I do a modal acoustic simulation, I am unable to see the results in the solution. So, I used user defined output result to calculate the Kinetic energy and thought to calculate modal mass value from the KE. I am not able to get the same modal mass value when I try to calculate modal mass using KE for the elastic beam problem (KE=1/2*mass*frequency^2, found from discussion). The units are also not clear from the analysis. I tried to see if I can get the same modal mass values for the elastic beam. I am not sure if this is a right approach. Do you have any suggestion on calculating the modal mass for each mode from modal acoustics?
      Thank you very much for your time and response.
      Best Krishna
    • krishnendu
      Subscriber
      Hi Any help on calculating the modal mass from the User defined Kinetic energy output for each mode shapes?
      I am unable to proceed to further steps, Please help me sort this issue with Ansys simulation analysis.
      Thank you Best Krishna
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