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-   -   gravity current modelling (http://www.cfd-online.com/Forums/fluent/88675-gravity-current-modelling.html)

asistas May 23, 2011 13:40

gravity current modelling
 
Hi!
I'm trying to model a simple gravity current flow Using FLUENT 12.0. It's a very simple one because I'll verify the model results by comparing them with experimental ones. Experimental flume is 4.25 m in length and 0.5 m in depth. first 0.25x0.25 is initially filled with water and at t=0 the lock is opened and gravity flow is recorded. To model this problem I've used. VOF implicit with enabled open channel flow and implicit body force options. For viscous model I've used k-epsilon Realizable with enhanced wall treatment (pressure gradient effects enabled).
The problem with the model is water propagates too slow. Could you let me a hand? Do you have an idea what i have done wrong?

Thank you so much for your time!

somy1 September 17, 2011 21:30

Quote:

Originally Posted by asistas (Post 308897)
Hi!
I'm trying to model a simple gravity current flow Using FLUENT 12.0. It's a very simple one because I'll verify the model results by comparing them with experimental ones. Experimental flume is 4.25 m in length and 0.5 m in depth. first 0.25x0.25 is initially filled with water and at t=0 the lock is opened and gravity flow is recorded. To model this problem I've used. VOF implicit with enabled open channel flow and implicit body force options. For viscous model I've used k-epsilon Realizable with enhanced wall treatment (pressure gradient effects enabled).
The problem with the model is water propagates too slow. Could you let me a hand? Do you have an idea what i have done wrong?

Thank you so much for your time!

------------------------------------------------------------

somy1 September 17, 2011 21:35

:confused:

ezzhisham September 18, 2011 11:50

Quote:

Originally Posted by asistas (Post 308897)
Hi!
I'm trying to model a simple gravity current flow Using FLUENT 12.0. It's a very simple one because I'll verify the model results by comparing them with experimental ones. Experimental flume is 4.25 m in length and 0.5 m in depth. first 0.25x0.25 is initially filled with water and at t=0 the lock is opened and gravity flow is recorded. To model this problem I've used. VOF implicit with enabled open channel flow and implicit body force options. For viscous model I've used k-epsilon Realizable with enhanced wall treatment (pressure gradient effects enabled).
The problem with the model is water propagates too slow. Could you let me a hand? Do you have an idea what i have done wrong?

Thank you so much for your time!

I want to model the same problem but in a sinuous channel. Actually I failed and I need any help. My problem is I found that the whole domain is filled with the denser fluid and no existence of the water (lighter fluid).
Please I need help in that.
Also, I'm searching for any open channel tutorial
if anybody knows please send me "ezz.hisham@gmail.com"

asistas September 23, 2011 21:02

Quote:

Originally Posted by somy1 (Post 324537)
:confused:

Hi Somy,

Thank you so much for your reply. I see that you've suggested me to give 0 to turbulent viscosity. I'm working with a domain filled with water and mud will have the gravity current in this domain. I still have a very slow propagation. Do you think setting 0 to turbulent viscosity will help?
(by the way i'm sorry for late reply)

somy1 September 24, 2011 03:01

Quote:

Originally Posted by asistas (Post 325431)
Hi Somy,

Thank you so much for your reply. I see that you've suggested me to give 0 to turbulent viscosity. I'm working with a domain filled with water and mud will have the gravity current in this domain. I still have a very slow propagation. Do you think setting 0 to turbulent viscosity will help?
(by the way i'm sorry for late reply)

hi
yea
it will help u. but isnot correct way.i read atticles that simulated this current whit k-epsilon model then turbulent viscosity con't be 0.
your current will propagate faster but i don't know velocity, pressure and etc profiles will be corret or no.
beacouse of this i earsed my pervious answer.

somy1 September 24, 2011 03:07

Quote:

Originally Posted by ezzhisham (Post 324567)
I want to model the same problem but in a sinuous channel. Actually I failed and I need any help. My problem is I found that the whole domain is filled with the denser fluid and no existence of the water (lighter fluid).
Please I need help in that.
Also, I'm searching for any open channel tutorial
if anybody knows please send me "ezz.hisham@gmail.com"

hi
Fluent's open chanel tutorial?
where are u comfrom?

ezzhisham September 24, 2011 09:17

Quote:

Originally Posted by somy1 (Post 325436)
hi
Fluent's open chanel tutorial?
where are u comfrom?

I'm a new fluent user. if you have something to help say it, if not please don't give comments

somy1 September 24, 2011 09:38

Quote:

Originally Posted by ezzhisham (Post 325465)
I'm a new fluent user. if you have something to help say it, if not please don't give comments

any new fluent user knows that there is not any help for open chanel simulation in fluent. u must read helps about vof and turbolance.

Yapoo September 24, 2011 16:20

Quote:

Originally Posted by somy1 (Post 325467)
any new fluent user knows that there is not any help for open chanel simulation in fluent. u must read helps about vof and turbolance.

Ansys fluent 12.0 tutorial has a example for open channel simulation with VOF method.

ezzhisham September 24, 2011 22:43

Quote:

Originally Posted by Yapoo (Post 325478)
Ansys fluent 12.0 tutorial has a example for open channel simulation with VOF method.

please I need it
my email is ezz.hisham@gmail.com


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