Guidance on Implementing the Synthetic Eddy Method for Turbulence Inlet Conditions

aliabdullahnust · May 21, 2023, 13:00

Hello everyone,

I'm currently working on a project in which I need to simulate turbulent flow in a duct. For the inlet boundary condition, I'd like to use the Synthetic Eddy Method (SEM) to superimpose synthetic turbulence onto the mean flow.

While I understand the basic theory behind SEM, I'm struggling a bit with the actual implementation in code. Specifically, I'm unsure about generating the eddies according to the energy spectrum, imposing a divergence-free condition, and handling eddies that exit the computational domain.

Would anyone be able to provide guidance or recommend resources (books, papers, online tutorials) that include detailed explanations or examples of SEM implementation in code? Additionally, are there any open-source CFD software or libraries that provide SEM as a built-in feature, which I could use as a reference?

Any advice or direction would be greatly appreciated!

LuckyTran · May 21, 2023, 14:00

The old synthetic eddy method which you are referring to comes from this paper. More recent papers such as by Skillen might go into more details that you care about and their source code can be found on this github.

Eddies that exit the computational domain are an entirely different issue that you don't need to worry about when coding an inlet. Eddies are partially reflected at domain exits and these are handled with non-reflecting boundary conditions. Or you can just do what 99% of ppl do and let them reflect.

May 21, 2023, 13:00	Guidance on Implementing the Synthetic Eddy Method for Turbulence Inlet Conditions	#1
aliabdullahnust New Member Ali Abdullah Join Date: Aug 2018 Posts: 3 Rep Power: 8	Hello everyone, I'm currently working on a project in which I need to simulate turbulent flow in a duct. For the inlet boundary condition, I'd like to use the Synthetic Eddy Method (SEM) to superimpose synthetic turbulence onto the mean flow. While I understand the basic theory behind SEM, I'm struggling a bit with the actual implementation in code. Specifically, I'm unsure about generating the eddies according to the energy spectrum, imposing a divergence-free condition, and handling eddies that exit the computational domain. Would anyone be able to provide guidance or recommend resources (books, papers, online tutorials) that include detailed explanations or examples of SEM implementation in code? Additionally, are there any open-source CFD software or libraries that provide SEM as a built-in feature, which I could use as a reference? Any advice or direction would be greatly appreciated!

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May 21, 2023, 14:00		#2
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,761 Rep Power: 66	The old synthetic eddy method which you are referring to comes from this paper. More recent papers such as by Skillen might go into more details that you care about and their source code can be found on this github. Eddies that exit the computational domain are an entirely different issue that you don't need to worry about when coding an inlet. Eddies are partially reflected at domain exits and these are handled with non-reflecting boundary conditions. Or you can just do what 99% of ppl do and let them reflect.