Hydraulic Diameter

ruzfactor · November 29, 2010, 19:46

I'm trying to solve a sudden expansion mesh in FLUENT using K-e model. I'm using turbulent intensity and hydraulic diameter for giving turbulence BC. I want to what should be the hydraulic diameter for a axisymmetric sudden expansion and also how do I guess the value of turbulence intensity?

pete · November 30, 2010, 04:10

CFD-Wiki contains an estimation of the turbulence intensity in a fully developed pipe flow. see http://www.cfd-online.com/Wiki/Turbulence_intensity. That page also links to the definition of the hydraulic diameter.

ruzfactor · November 30, 2010, 07:49

For a sudden expansion there are two diameters. which one should be taken into account when I'm interested only the flow behaviour at the downstream of the expansion.

can you please help me setting the BC for a sudden expansion?? I really need some help here.

pete · November 30, 2010, 07:53

What you want to compute are boundary conditions at the inlet, right? Then it is the inlet dimensions that you should use.

ruzfactor · November 30, 2010, 08:13

yes. BC at inlet.

siri · November 30, 2010, 08:15

so simple!

n eureka ! i just discovered that .. any response < 10 characters won't get submitted to the forum.

P.S: was it to stop spam ?

ruzfactor · November 30, 2010, 08:46

I'm posting the pics of sudden expansion. The inlet dimensions were variable in the actual experiment but How do I do that in the given mesh? I have to compare the results with the experimental data.

November 29, 2010, 19:46	Hydraulic Diameter	#1
ruzfactor New Member RUZ Join Date: Oct 2010 Posts: 25 Rep Power: 16	I'm trying to solve a sudden expansion mesh in FLUENT using K-e model. I'm using turbulent intensity and hydraulic diameter for giving turbulence BC. I want to what should be the hydraulic diameter for a axisymmetric sudden expansion and also how do I guess the value of turbulence intensity?

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November 30, 2010, 04:10		#2
pete Administrator Peter Jones Join Date: Jan 2009 Posts: 682 Rep Power: 10	CFD-Wiki contains an estimation of the turbulence intensity in a fully developed pipe flow. see http://www.cfd-online.com/Wiki/Turbulence_intensity. That page also links to the definition of the hydraulic diameter.

November 30, 2010, 07:49		#3
ruzfactor New Member RUZ Join Date: Oct 2010 Posts: 25 Rep Power: 16	For a sudden expansion there are two diameters. which one should be taken into account when I'm interested only the flow behaviour at the downstream of the expansion. can you please help me setting the BC for a sudden expansion?? I really need some help here.

November 30, 2010, 07:53		#4
pete Administrator Peter Jones Join Date: Jan 2009 Posts: 682 Rep Power: 10	What you want to compute are boundary conditions at the inlet, right? Then it is the inlet dimensions that you should use.

November 30, 2010, 08:13		#5
ruzfactor New Member RUZ Join Date: Oct 2010 Posts: 25 Rep Power: 16	yes. BC at inlet.

November 30, 2010, 08:15		#6
siri Member Join Date: Oct 2010 Posts: 45 Rep Power: 16	so simple! n eureka ! i just discovered that .. any response < 10 characters won't get submitted to the forum. P.S: was it to stop spam ?