LES of Ribbed Channel

Matteo85 · June 29, 2009, 12:31

Hi,
I'm working on the LES and DES simulation of the flow with heat transfer in a ribbed square channel (only one rib placed on one of the surfaces of the channel, on which surface a constant-heat flux condition is to be applied) with cyclic boundary conditions at inlet and outlet. I adopted a numerical work (by Liu, Tucker, Lo Iacono, 2006) as a reference for the setup of my case, in particular as regards the additional term that is required both in the momentum and in the energy equation as a consequence of the utilization of cyclic boundary conditions. The results of my calculations are not satisfactory in terms of velocity field above the ribbed surface, nor in term of distribution of Nusselt number: I'd like to know if anyone has had experience with this kind flow, in particular I'm interested in cross-checking the expression of the additional terms as well as the application of a fixed-gradient condition for the temperature at the heated wall to represent the constant-heat flux condition.

Your help would be really welcome,
Bye

Matteo

santos · June 29, 2009, 12:45

What solver did you use? channelOodles?

Regards,
Jose Santos

Matteo85 · June 30, 2009, 02:42

Hi Santos,

thanks for replying,
yes I've been using a solver that is based on ChannelOodles, I mean the momentum equation is solved as in ChannelOodles, but I've had to add the energy equation (equation for temperature). I've tried to use the energy equation in 2 forms: with a source term (as explained by Liu in the paper I cited in last post); without source term, but imposing a temperature jump between inlet and outlet.
As regards the momentum equation, although the authors of the cited paper report successfull results obtained with a source term similar to the one employed by ChannelOodles (i.e. calculated as a a mean quantity for the entire channel ), I'm not so sure this kind of source term is suitable for a channel with a rib.

Thanks again,

have a nice day

Matteo

June 29, 2009, 12:31	LES of Ribbed Channel	#1
Matteo85 New Member Matteo Baldi Join Date: Mar 2009 Location: Pistoia, Italy Posts: 9 Rep Power: 17	Hi, I'm working on the LES and DES simulation of the flow with heat transfer in a ribbed square channel (only one rib placed on one of the surfaces of the channel, on which surface a constant-heat flux condition is to be applied) with cyclic boundary conditions at inlet and outlet. I adopted a numerical work (by Liu, Tucker, Lo Iacono, 2006) as a reference for the setup of my case, in particular as regards the additional term that is required both in the momentum and in the energy equation as a consequence of the utilization of cyclic boundary conditions. The results of my calculations are not satisfactory in terms of velocity field above the ribbed surface, nor in term of distribution of Nusselt number: I'd like to know if anyone has had experience with this kind flow, in particular I'm interested in cross-checking the expression of the additional terms as well as the application of a fixed-gradient condition for the temperature at the heated wall to represent the constant-heat flux condition. Your help would be really welcome, Bye Matteo

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June 29, 2009, 12:45		#2
santos Senior Member Jose Luis Santos Join Date: Mar 2009 Location: Portugal Posts: 215 Rep Power: 18	What solver did you use? channelOodles? Regards, Jose Santos

June 30, 2009, 02:42		#3
Matteo85 New Member Matteo Baldi Join Date: Mar 2009 Location: Pistoia, Italy Posts: 9 Rep Power: 17	Hi Santos, thanks for replying, yes I've been using a solver that is based on ChannelOodles, I mean the momentum equation is solved as in ChannelOodles, but I've had to add the energy equation (equation for temperature). I've tried to use the energy equation in 2 forms: with a source term (as explained by Liu in the paper I cited in last post); without source term, but imposing a temperature jump between inlet and outlet. As regards the momentum equation, although the authors of the cited paper report successfull results obtained with a source term similar to the one employed by ChannelOodles (i.e. calculated as a a mean quantity for the entire channel ), I'm not so sure this kind of source term is suitable for a channel with a rib. Thanks again, have a nice day Matteo