Boundary conditions in hydrostatic fluid not activated

- May 24, 2022 at 5:55 pm
  
  i.tamunodienye2
  Subscriber
  
  Hi Please how do I activate the elements and boundary conditions for hydrostatic fluid simulation? Apart from HSFLD element creation, the other boundary conditions are not activated.
  Please i would need your help.
  
  Thanks
- May 25, 2022 at 6:25 am
  
  Erik Kostson
  Ansys Employee
  
  Hi
  
  We can not provide any help with act extensions - the only thing we can say is to use the act extension with the correct version, because some extensions are not updated and can not be used say with a 2022 R1 release. Finally what are you trying to do with a modal analysis and these elements ?
  
  Erik
- May 26, 2022 at 5:29 pm
  
  i.tamunodienye2
  Subscriber
  
  I want to use modal analysis to find the natural frequency of a complex pipe structure when filled with fluid. So the hydrostatic fluid element HSFLD242 is what i intend to use. If you have another appropriate method to go about this please kindly help me.
  I am using ansys 2020R2.
  I tried to follow these steps ACT_Hydrostatic Fluid Extension.pdf
  I got the ACT hydrostatic fluid from the ansys app store Ansys Store Hydrostatic FluidV202.1 created by ANSYS Inc. Though it is V202.1, they stated that the V202.1 can support both 2020R1 and 2020R2. To my disappointment not all the features are activated and i have been on this for several months. Pls how may you help me. I just have few months to submit my work.
  
  Thanks
- May 27, 2022 at 6:37 am
  
  Erik Kostson
  Ansys Employee
  
  Hi ´╗┐@Tams´╗┐
  
  The correct elements to use here to account for the fluid added
  mass exerted by the fluid on the pipe (and other interactions) are the acoustic elements (FLUD220/FLUID221).
  SO you need a modal acoustic analysis with structure and fluid present, and sharing topology (in Spaceclaim or Design modeler) between them.
  
  See the below discussions on this workflow:
  
  /forum/index.php?p=/discussion/24433/fsi-problem
  https://www.ijeast.com/papers/323-335,Tesma404,IJEAST.pdf
  https://www.mechsol.com/blog/accurately-predicting-structural-and-acoustic-pipe-resonance
  
  Erik
  
  For your info and reference only:
  THe HSFLD elements are for hydrostatic calculation and do not
  provide the correct added mass from the fluid on a vibrating structure so they
  are not used here (modal) and are only for static calculations (like inflatable
  gasket/balloon type of problems, etc.).
- May 27, 2022 at 8:26 am
  
  i.tamunodienye2
  Subscriber
  
  I can't thank you enough for the help and direction you have provided me.
  I'm so grateful for the information. I will start working on this immediately and communicate back if anything else.
  
  Thank you