help on separating laminar and trubulent region
 

I am wondering if Fluent would allow me to separate a domain into two part: one part is to be simulated by solving the laminar NS equations and the second part is a continous flow of the first part but I need to use a RANS model there. For example, for flow across a circular cylinder in the sub-critical regime, I wish to solve laminar equations in the front half of the cylinder but RANS in the rear half. Any experiences or suggestions?

Your help is highly appreciated!

Zhihua

Re: help on separating laminar and trubulent regio
 

read the portion of turbulence model fluent users guide

Re: help on separating laminar and trubulent regio
 

Thank you for your help. I read the part on turbulence model but I did not find any information on how to simulate laminar and turbulence together. Is there a way to defined laminar zone and turbulent zone in one domain?

Zhihua

Re: help on separating laminar and trubulent regio
 

When creating your mesh, you need to define separate zones for the turbulent and laminar regions of the model. Then, in FLUENT, you enable your desired turbulence model and in the boundary conditions panel for the laminar zone set it to laminar.

Re: help on separating laminar and trubulent regio
 

Thank you, Evan! I have set the laminar zone. But when I tried to initialize the whole domain, the following information show up: WARNING: Unassigned interface zone detected for interface 4 Error: Init_Flow: unassigned interface_zones Error Object: #f

I think this means I need to set a special boundary condition at the "interface" between the laminar and turbulent zone. Can you help me with that?

Thanks!

Zhihua

Re: help on separating laminar and trubulent regio
 

I've never seen this particular error before. Check to make sure that whatever is separating the two regimes is a "default interior". That's all I can think of.

Re: help on separating laminar and trubulent regio
 

It works now. Thank you for your help, Evan.

Zhihua