Is it possible to define different time step sizes in a system coupling simulation?

DanielOliveira

I'm performing one-way FSI simulation with Fluent and Structures using system coupling module.

My question is: Is it possible to define a specific time step for Fluent model, other for the Structures model (being a multiple of the Fluent one) and then define a system coupling equal to the Structures?

As example:

Fluent time step: 0.01

Structures time step: 0.1

System Coupling time step: 0.1

So, fluent model performs 10 time steps and then transfer the data for the structural model.

Thanks

Luigi0

Hi DanielOliveira,

I am not an expert, but I'm working on coupled analysis using system coupling. As fa as I know the time step must be the same for fluent and mechanical, also because the time step is controlled by the system coupling.

Some useful tutorials can be found at these links : https://www.youtube.com/watch?v=oOGkvrnKS-c, https://www.youtube.com/watch?v=ef9XGXyuJHY

I repeat that i am not an expert, so you can wait for a more comprehensive answer.

Good luck!

Steve

That's correct, the timestep must be the same for both solvers.

DanielOliveira

Really appreciate your answers.

So, is it possible to simulate first 5 s in Fluent independently, to stablize de fluid flow, and after use that data as initial data for System Coupling simulation?

Thanks

Steve

Hi @DanielOliveira , yes that's possible and that's something that is commonly done to initialize the flow field.

DanielOliveira

Hi @Steve, can you explain me how to do that?

It could help me to save a lot of computational time and space.

Really appreciate

azing

Hi @DanielOliveira , did you figure out how to start the coupled simulation from a later time step?

I am using Fluent in combination with a nonlinear system and the spike at the beginning of the simulation affects my results since it yield the nonlinear system.

Thanks,

Azin