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How to Set Up Passive Rigid Body in nanoFluidX

Hi,

I would like to create a simulation of a rigid body floating on the water surface or moving through the water. I'm planning to use the Passive Rigid Body feature for testing. I have currently input the initial velocity and constant speed, but the log file shows the following error:

Error: [EIO95] Cannot find/open the preset time dependent linear velocity file (prbcon_linvel_f_c) "" for passive rigid body motion 1.

Do I need to import any additional files, or are there other settings required?

DataBase1.slb (2).zip

If anyone knows, please reply. Thank you!

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Accepted answers

acupro

It looks like you should use the data you've entered in Time Series Velocity instead. You probably also need to specify a Reference Velocity - maybe use the same as your initial/constant velocity - in Solver Settings > Time Step Settings.

All comments

acupro

Zhijia_Lin

Hello, acupro:

Thank you! I am now able to start the analysis as the previous issue has been resolved.I would like to understand the meaning of ref_velocity in the time step. Does it refer to the initial velocity assigned to my object, or does it have a different significance?After completing my analysis, I noticed that my rigid body did not move forward at 50 mm/s and remained stationary. Could it be that my input was not accurate enough?

If you have any insights, please let me know. Thank you!

acupro

The reference velocity (ref_vel) is approximately the highest fluid velocity you expect to have in the domain. Then you can scale that with reference velocity factor (ref_vel_factor) to be more conservative. You can search for those parameters in this page:
https://help.altair.com/hwcfdsolvers/nfx/topics/command_ref/domain_ref_r.htm

If you can attach the .cfg file you used, that could be helpful.

What is your intent here? Do you want the body to move forward with 50 mm/s - AND behave as a Passive Rigid Body at the same time? In which DOFs do you wish the passive rigid body motion to be active? (3 translations, 3 rotations available) What is the real-world scenario here?