CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > FLUENT

Turbidity current

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   June 25, 2012, 20:12
Default Turbidity current
  #1
New Member
 
Julien.n
Join Date: Jun 2012
Posts: 1
Rep Power: 0
julien.n is on a distinguished road
Hello everyone,

I am working in a lab where we make some experiments on turbidity currents,
so I am trying to modelize a turbidity current with Fluent to compare the numerical results with the experimental ones.


I've got some difficulties to obtain a good model which is matching
with reality.
I'm using fluent 14 with a simple geometry (a flume 0.580x5x0.4m or
0.580x5m in 2d) meshed with Gambit (40 000 cells approximately).
I've put water in the flume.

I tried to introduce a turbidity current by a
velocity inlet in the left side, 0.5 m/s for velocity, 0.1 for volume
fraction of sediment, and 20% for the turbulence intensity.

(I also tried to patch a sediment suspension in the left part of the flume
(density 2500 kg/m3) with a volume fraction of 1 then 0.4, 0.2, 0.1
with water and 20% for turbulence intensity I tried all of them.
Then I've injected water by the left side, I tried different
velocities 10m/s 1m/s 0.5m/s 0.1m/s 0.01 m/s).

I used a pressure based transient model with gravity, and an implicit
Eulerian multiphase model.
For turbulence I used k-epsilon model with RNG, standard wall
functions and dispersed turbulance multiphase model.
Then I've put the granular option in the sediment phase with a
syamlal-obrien interaction with water.

When I solve this problem, I have not got the billows or just the
first one in the head but not in the body.
I posted some movies and pictures here :
https://docs.google.com/folder/d/0B7...VEk/edit?pli=1

What I want to obtain is a model with all the billows of the turbidity current like we can see on this videos for exemple : http://video.google.com/videoplay?do...40257860282305


I tried a lot of different model, parameters, turbulence options ... and I always have an imprecise model (without the billows) so I would like to understand what is wrong with my approach.


Thank you.

Julien
julien.n is offline   Reply With Quote

Reply

Tags
fluent, turbidity current


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
What is the difference between current time step and current time djing FLUENT 4 May 1, 2012 17:18
saline gravity current asistas FLUENT 3 October 24, 2011 14:18
dilute gravity current at very flow base doronzo FLUENT 0 October 5, 2011 16:38
current density design in fuel cells kumar FLUENT 0 November 18, 2005 17:55
Cells of current line in three dimensionnal flow GACEM_hatem Phoenics 2 June 18, 2001 10:38


All times are GMT -4. The time now is 19:24.