Velocity BC on a Fixed Body

Hello SimScale team,

I have a bunch of questions.

Question 1
What happens if I prescribe a velocity boundary condition to a solid body (a subdomain) which already is has fixed support BC on all its sides? Will the subdomain move or not?

Question 2
What happens if I prescribe velocity BC (for example: V_x =1m/s) and keep the timestep of my dynamic simulation on an order of magnitude smaller (0.1 s)? Will the model prescribe that fractional value of velocity BC to the domain in each of the timestep (for example U_x=0.1m per 0.1s in the above case)?

Thank you
Viven

Hello Viven!

Regarding question number 1, I would expect no movement overall in case the body is constrained by fixed support on all sides. It’s possible that you will obtain small amount of displacements inside the solid body since the velocity is assigned to whole body while the fixed support is applied to only covering surfaces.

About the second question, yes. In this case, displacement in each time step will be computed by multiplying the time step and velocity unless the body is not constrained by any other boundary conditions.

I hope this is helpful,
Best.

Hi Kaany,

Indeed that was helpful and I tried implementing the same in my model. However the model subdomain doesn’t seems to moving the way it should. This refers to Run-7 of this model link.
In this model I constrained a rigid body (lower subdomain) using symmetric BC and applied surface parallel velocity, but the displacement seems to still be zero (pic below).

What could be going wrong here?

Thanks again for the reply.
Viven

Hello Viven!

The project seems private, is it possible that you can make it public?

Best.

Hi Kaany,

Sorry about that. You seem to be member of SimScale team. What’s your email id, the one I can use to share the model with you?

Edit: I have selected the “share with support” option, in sharing controls, let me know if you still can’s access it.

Thanks again
Viven

Hello SimScale team,

I am still looking to apply directional displacement parallel to a symmetric BC. Can anyone provide some help in this regard.

Thank you
Viven