CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Running, Solving & CFD

Flow Past a cylinder- Re-1000-PisoFoam Solver

Register Blogs Members List Search Today's Posts Mark Forums Read

Like Tree2Likes

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   October 24, 2015, 14:02
Default
  #21
New Member
 
vito
Join Date: Jun 2015
Posts: 22
Rep Power: 10
vitocorleone is on a distinguished road
Davi,

Firstly, My suggestion is to use pimple Foam Solver when you are setting up LES, not pisoFoam ( they are essentially same when no. of outer corrector loops is 1).

MESH
As far Mesh refinement goes, the approach was very simple. I kept refining my mesh near wall of the cylinder till i got the Yplus value around 1, in my my case yplus was around 1.5, but lot of literature suggests it should be less than 1 to ofcourse capture the viscous effects in the boundary layer.
But for your initial cases you can start of with a y plus a little greater than1. Also when you use Yplus LES utility in Openfoam it tends to give a slightly larger value in the initial few time steps but then tends go down much later in the simulation when the flow steadies out.

Time step
As you may already know, the beauty of pimple foam is such that you can specify a courant number and the solver will vary the time step to suit your courant number specification, so I started off 1e-04 for a reynolds of re=3900 and you should be fine with this. I used max courant number to be 0.5.


My files are in a different computer and will not be able to post them until monday. But essentially the mesh is same as i have posted before but finer near the wall.Hope this helps till then.
davibarreira likes this.
vitocorleone is offline   Reply With Quote

Old   October 24, 2015, 14:07
Default
  #22
Member
 
Davi Barreira
Join Date: Apr 2014
Location: Fortaleza
Posts: 76
Rep Power: 11
davibarreira is on a distinguished road
It does help, thank. I'm also using pimple with outer corrector equal to 1. I've been using y+ around 1 already for some of the RANS models, so I guess the meshes Im using could work, the only thing is that I use a lot of local refinement and I've read that they might affect the solution, since the filtering will be different in the domain. What model for LES did you use? OneEquation, Smagorisnky...?
davibarreira is offline   Reply With Quote

Old   October 24, 2015, 14:09
Default
  #23
New Member
 
vito
Join Date: Jun 2015
Posts: 22
Rep Power: 10
vitocorleone is on a distinguished road
I used the no. of outer loops 3

I used one-eqn and no damping or anything. Yeah I have not dived in to the depth of filters although I know that the domain size should be same in x, y and z directions.
vitocorleone is offline   Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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
Fluent + flow past cylinder at Re=40 m.vegad Main CFD Forum 25 January 9, 2018 01:34
Flow past a cylinder. Help needed Lurapa Main CFD Forum 1 August 18, 2013 12:25
[ICEM] Flow past a 2D cylinder arun7328 ANSYS Meshing & Geometry 0 February 15, 2013 13:17
Drag coefficient of flow past cylinder vs time pedroxramos FLUENT 0 January 14, 2013 13:39
Flow past 2 smooth circular cylinder slip FLUENT 0 July 8, 2010 19:45


All times are GMT -4. The time now is 03:30.