Turn inlet and outlet to boundary condition

matos · December 28, 2018, 06:45

Hello,
I am using a reactor which was initially simulated, in transient state, with two inlets (at the bottom) and and two outlets (at the top). Now that the dynamic behaviour of the fluids inside the reactor is stabilized, I want to transform the inlets (inlet 1 and 2) and outlets (outlet 1 and 2) into a boundary condition, i.e., what goes out through inlet 1 will reenter in inlet 1 and the same for inlet and outlet 2.
I transformed the inlet 1 and outlet 1 into walls (81 and 113) and tryied to use the manual boundary condition comands:

/mesh/modify-zones> make-periodic
Periodic zone [()] 81
Shadow zone [()] 113
Rotational periodic? (if no, translational) [yes] yes
Create periodic zones? [yes] yes

But I get this error:

Error: Failed to make zones periodic.
Error Object: #f

Am I doing something wrong or it is not possible to do this ?
Thank you in advance,
Joana Matos.

LuckyTran · December 30, 2018, 15:12

Why did you answer yes to rotational? That's your problem.

Note that for the periodic pair creation to be successful the grid needs to be conformal at the boundaries. Otherwise you need to create a periodic interface.

matos · December 30, 2018, 15:20

Thank you. Actually I tried both rotational and translational. I changed the mesh so it is conformal and the perioidc boundaries, with translational, are done. I'm having convergence problems now: "floating point". I tried several methods, but could not solve the problem...

December 28, 2018, 06:45	Turn inlet and outlet to boundary condition	#1
matos New Member Maria Join Date: Apr 2018 Posts: 4 Rep Power: 7	Hello, I am using a reactor which was initially simulated, in transient state, with two inlets (at the bottom) and and two outlets (at the top). Now that the dynamic behaviour of the fluids inside the reactor is stabilized, I want to transform the inlets (inlet 1 and 2) and outlets (outlet 1 and 2) into a boundary condition, i.e., what goes out through inlet 1 will reenter in inlet 1 and the same for inlet and outlet 2. I transformed the inlet 1 and outlet 1 into walls (81 and 113) and tryied to use the manual boundary condition comands: /mesh/modify-zones> make-periodic Periodic zone [()] 81 Shadow zone [()] 113 Rotational periodic? (if no, translational) [yes] yes Create periodic zones? [yes] yes But I get this error: Error: Failed to make zones periodic. Error Object: #f Am I doing something wrong or it is not possible to do this ? Thank you in advance, Joana Matos.

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December 30, 2018, 15:12		#2
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,674 Rep Power: 65	Why did you answer yes to rotational? That's your problem. Note that for the periodic pair creation to be successful the grid needs to be conformal at the boundaries. Otherwise you need to create a periodic interface.

December 30, 2018, 15:20		#3
matos New Member Maria Join Date: Apr 2018 Posts: 4 Rep Power: 7	Thank you. Actually I tried both rotational and translational. I changed the mesh so it is conformal and the perioidc boundaries, with translational, are done. I'm having convergence problems now: "floating point". I tried several methods, but could not solve the problem...