About Reynolds stresses

Shayankhan · January 19, 2019, 07:38

Greetings community members,
I need a small help. I am working on an open channel flow in the presence of vegetation using Fluent. My Reynolds stress (u'w') values in the vertical profile are maximum (peak) but negative, close to the top of vegetation and bed.
Do, I need to reverse the sign of all the values ?? As I am confused about its definition given in Fluent manual user guide help which is "-ρuiuj".
Or should I take the same sign of the readings as obtained by the model ?? (This should probably the case if model automatically includes the negative sign during its calculation).

LuckyTran · January 19, 2019, 12:08

No you don't need to flip the sign. The Reynolds stresses are defined as positive uiuj. Where in the manual do you find it defined as "-ρuiuj" ? That would be a mistake. Please submit a bug report to the customer service center.

Shayankhan · January 19, 2019, 22:27

Dear LuckyTran,
Thank you for your help.

January 19, 2019, 07:38	About Reynolds stresses	#1
Shayankhan New Member Naveed Join Date: Dec 2016 Location: Saitama, Japan Posts: 11 Rep Power: 9	Greetings community members, I need a small help. I am working on an open channel flow in the presence of vegetation using Fluent. My Reynolds stress (u'w') values in the vertical profile are maximum (peak) but negative, close to the top of vegetation and bed. Do, I need to reverse the sign of all the values ?? As I am confused about its definition given in Fluent manual user guide help which is "-ρuiuj". Or should I take the same sign of the readings as obtained by the model ?? (This should probably the case if model automatically includes the negative sign during its calculation).

January 19, 2019, 12:08		#2
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,751 Rep Power: 66	No you don't need to flip the sign. The Reynolds stresses are defined as positive uiuj. Where in the manual do you find it defined as "-ρuiuj" ? That would be a mistake. Please submit a bug report to the customer service center. Shayankhan likes this.

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January 19, 2019, 22:27		#3
Shayankhan New Member Naveed Join Date: Dec 2016 Location: Saitama, Japan Posts: 11 Rep Power: 9	Dear LuckyTran, Thank you for your help.