V2f model , Fluent's background

August 11, 2006, 12:10

Does anybode have the v2f model fluent's help?

pleaseeee.

August 21, 2006, 02:32

The v2-f Model The v2-f model is similar to the standard k- model, but incorporates near-wall turbulence anisotropy and non-local pressure-strain eects. It is a general low-Reynoldsnumber turbulence model that is valid all the way up to solid walls, and therefore does not need to make use of wall functions. Although the model was originally developed for attached or mildly separated boundary layers [65], it also accurately simulates ows dominated by separation . The distinguishing feature of the v2-f model is its use of the velocity scale, v2, instead of the turbulent kinetic energy, k, for evaluating the eddy viscosity. v2, which can be thought of as the velocity uctuation normal to the streamlines, has shown to provide the right scaling in representing the damping of turbulent transport close to the wall, a feature that k does not provide. For more information about the theoretical background and usage of the v2-f model, please visit the Fluent User Services Center (www.fluentusers.com).

hamide · July 11, 2016, 16:32

hi all
i want to simulate turbulent flow in a 2D channel (2*40cm) by v2f model.
i set it as follow:
-i try to use fine mesh near the wall, (y+<=1)
-B.C : velocity inlet, v=5 m/s , and define functions for v,k,epsilon and v2.(to be fully developed from beginning of channel)
outFlow for end of the channel
nosleep fo walls.
-second order upwind to solve equations.

but unfortunately i can't valid my results!!!!!!

for example i can't find u+ vs y+ graph correctly!!! and also v'+ vs y+ and k+ vs y+ near the wall!!!!(1<y+<100)

i don't know what the problem is!!!!

is there any one help me to handle this problem.

August 11, 2006, 12:10	V2f model , Fluent's background	#1
pablo Guest Posts: n/a	Does anybode have the v2f model fluent's help? pleaseeee.

August 21, 2006, 02:32	Re: V2f model , Fluent's background	#2
hossein Guest Posts: n/a	The v2-f Model The v2-f model is similar to the standard k- model, but incorporates near-wall turbulence anisotropy and non-local pressure-strain eects. It is a general low-Reynoldsnumber turbulence model that is valid all the way up to solid walls, and therefore does not need to make use of wall functions. Although the model was originally developed for attached or mildly separated boundary layers [65], it also accurately simulates ows dominated by separation . The distinguishing feature of the v2-f model is its use of the velocity scale, v2, instead of the turbulent kinetic energy, k, for evaluating the eddy viscosity. v2, which can be thought of as the velocity uctuation normal to the streamlines, has shown to provide the right scaling in representing the damping of turbulent transport close to the wall, a feature that k does not provide. For more information about the theoretical background and usage of the v2-f model, please visit the Fluent User Services Center (www.fluentusers.com).

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July 11, 2016, 16:32		#3
hamide New Member hamide hayati Join Date: Oct 2015 Posts: 28 Rep Power: 10	hi all i want to simulate turbulent flow in a 2D channel (2*40cm) by v2f model. i set it as follow: -i try to use fine mesh near the wall, (y+<=1) -B.C : velocity inlet, v=5 m/s , and define functions for v,k,epsilon and v2.(to be fully developed from beginning of channel) outFlow for end of the channel nosleep fo walls. -second order upwind to solve equations. but unfortunately i can't valid my results!!!!!! for example i can't find u+ vs y+ graph correctly!!! and also v'+ vs y+ and k+ vs y+ near the wall!!!!(1<y+<100) i don't know what the problem is!!!! is there any one help me to handle this problem.