How to choose the Turbulance Intensity if I know RE number？

adam_annie · January 24, 2010, 12:06

Hi,everyone, how can i choose the Turbulance Intensity like "Low Intensity 1%", "Medium Intensity 5%", if I only know the Re number. Does that mean, the larger the Re number, the less Intensity of Turbulance. Thanks a lot.

ghorrocks · January 24, 2010, 19:17

The turbulence intensity and Re are independent variables. Turbulence intensity is the ratio of the energy in the flow turbulence over the energy of the bulk flow, so is dependent on upstream flow conditions.

For instance, a car driving at 100 km/h is operating at a certain Re number. The incoming flow turbulence intensity the car sees will change dramatically from when there is no car in front (ie low turbulence intensity) to when the car is following another car (ie high turbulence intensity). In both cases the car is operating at the same Re number, but the turbulence intensity is very different.

January 24, 2010, 12:06	How to choose the Turbulance Intensity if I know RE number？	#1
adam_annie New Member Yibin Dou Join Date: Dec 2009 Posts: 13 Rep Power: 16	Hi,everyone, how can i choose the Turbulance Intensity like "Low Intensity 1%", "Medium Intensity 5%", if I only know the Re number. Does that mean, the larger the Re number, the less Intensity of Turbulance. Thanks a lot.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
decay of turbulence intensity	littlelz	CFX	3	May 16, 2014 16:44
Question on Turbulence Intensity	Eric	FLUENT	1	March 7, 2012 04:30
how to choose turbulance models	t.sekhar babu	FLUENT	1	May 15, 2008 08:14
turbulance intensity	majesticcc	FLUENT	3	March 3, 2006 11:35

January 24, 2010, 19:17		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	The turbulence intensity and Re are independent variables. Turbulence intensity is the ratio of the energy in the flow turbulence over the energy of the bulk flow, so is dependent on upstream flow conditions. For instance, a car driving at 100 km/h is operating at a certain Re number. The incoming flow turbulence intensity the car sees will change dramatically from when there is no car in front (ie low turbulence intensity) to when the car is following another car (ie high turbulence intensity). In both cases the car is operating at the same Re number, but the turbulence intensity is very different.