Gas flow in vortex tube - LES and grid resolution

bernarde · March 26, 2009, 02:43

Hi all

We are currently working on a project where we have gas flowing in a vortex tube. The gas is flowing at high velocity (and high Mach number). From the work of JJ Derksen (Simulations of confined turbulent vortex flow, Comupters and Fluids 34 (2005)) I found they made use of LES with a Lattice Boltzmann method. However they the LB method is as yet now effective for high mach number compressible flows.

We are using Star-CCM+, and I have started a simulation with LES with the Smagorinsky SGS, but I am struggeling to reproduce the results obtained by Derksen. I am also unsure about the grid refinement required for LES.

I would like to find out anyone has effectivly simulated confined gas vortex flow (not using Lattice Boltzmann method).

Thanks in advance.

Bernard

harishg · March 26, 2009, 10:50

What kind of discretization scheme do you employ for the convection terms ? Make sure to keep it non dissipative to avoid numerical errors. My guess is your flow may have high velocity gradients. What is your geometry size and the meshing that you employ now ? Dynamic smagorinsky or LDKM might be a better option.

March 26, 2009, 02:43	Gas flow in vortex tube - LES and grid resolution	#1
bernarde Member Bernard Esterhuyse Join Date: Mar 2009 Location: Pretoria, South Africa Posts: 50 Rep Power: 17	Hi all We are currently working on a project where we have gas flowing in a vortex tube. The gas is flowing at high velocity (and high Mach number). From the work of JJ Derksen (Simulations of confined turbulent vortex flow, Comupters and Fluids 34 (2005)) I found they made use of LES with a Lattice Boltzmann method. However they the LB method is as yet now effective for high mach number compressible flows. We are using Star-CCM+, and I have started a simulation with LES with the Smagorinsky SGS, but I am struggeling to reproduce the results obtained by Derksen. I am also unsure about the grid refinement required for LES. I would like to find out anyone has effectivly simulated confined gas vortex flow (not using Lattice Boltzmann method). Thanks in advance. Bernard

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March 26, 2009, 10:50		#2
harishg Senior Member N/A Join Date: Mar 2009 Posts: 189 Rep Power: 17	What kind of discretization scheme do you employ for the convection terms ? Make sure to keep it non dissipative to avoid numerical errors. My guess is your flow may have high velocity gradients. What is your geometry size and the meshing that you employ now ? Dynamic smagorinsky or LDKM might be a better option.