Mechanisms of turbulence production

wilson · December 9, 2009, 12:27

I'm doing tutorial 9 in cfx and I am trying to answer a question about the main mechanisms of turbulence production in the different principal regions of the flow, can anyone tell me what this means please? I have attached a plot of eddy viscosity along the pipe.

Thanks

ghorrocks · December 9, 2009, 17:35

Sounds like you need to read a turbulence textbook. Have a look at "Turbulence Modelling for CFD" by Wilcox. It will explain turbulence generation mechanisms nicely.

wilson · December 9, 2009, 18:20

Thanks very much, I'll give that a look.

I spoke to someone who said that it is generated due to the deep velocity gradients but I'm looking for a more detailed explanation so hopefully this textbook will give me that

ghorrocks · December 10, 2009, 07:22

If you want the one-sentence answer, then yes, shear layers are a common source of turbulence.

M.J. · December 10, 2009, 14:28

what exactly are shear layers?

ghorrocks · December 10, 2009, 18:00

Regions of high fluid shear, for example boundary layers or the edge of fluid jets. Again, refer to the textbook I mentioned above.

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December 9, 2009, 17:35		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,872 Rep Power: 144	Sounds like you need to read a turbulence textbook. Have a look at "Turbulence Modelling for CFD" by Wilcox. It will explain turbulence generation mechanisms nicely.

December 9, 2009, 18:20		#3
wilson New Member Mike Join Date: Dec 2009 Posts: 14 Rep Power: 17	Thanks very much, I'll give that a look. I spoke to someone who said that it is generated due to the deep velocity gradients but I'm looking for a more detailed explanation so hopefully this textbook will give me that

December 10, 2009, 07:22		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,872 Rep Power: 144	If you want the one-sentence answer, then yes, shear layers are a common source of turbulence.

December 10, 2009, 14:28		#5
M.J. New Member Carley Join Date: Dec 2009 Posts: 1 Rep Power: 0	what exactly are shear layers?

December 10, 2009, 18:00		#6
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,872 Rep Power: 144	Regions of high fluid shear, for example boundary layers or the edge of fluid jets. Again, refer to the textbook I mentioned above.