CFD Online Logo CFD Online URL
Home > Forums > Phoenics

submerged circular jet

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

LinkBack Thread Tools Display Modes
Old   May 12, 2006, 02:16
Default submerged circular jet
Posts: n/a
I am modeling submerged circular jet (6mm dia), which is injecting at velocity of 70 m/s along x-axis. Domain size is (x-1.5m, y-0.75m, z-0.75m). I am using k-e model and elliptical-straggered equation for steady state solution.

Solution is not converging, it starts oscillating I have given relaxation (P1= -0.75, U1= 0.3,V1= 0.3, W1= 0.3 and K.E= -0.75) I have meshed jet into 3 along x-plane and y-plane

  Reply With Quote

Old   May 12, 2006, 08:38
Default Re: submerged circular jet
Posts: n/a
You do not say if the automatic convergence wizard CONWIZ=T or F, which is the default for recent versions of PHOENICS. If CONWIZ=F, try false time step relaxation on the velocities equal to 0.02/NX seconds, thereby making the false-transient relaxation terms the same order of magnitude as the convection terms in the momentum equations. I would use linear relaxation of 0.5 on the turbulence transport equations, but ensure that the turbulence linearisation parameter KELIN=3.

  Reply With Quote

Old   May 15, 2006, 01:16
Default Re: submerged circular jet
Posts: n/a
i have make the automatic convergence wizard CONWIZ=T i am using PHOENICS 3.6 even then i am not able to get the convergence

  Reply With Quote

Old   July 14, 2006, 15:37
Default Re: submerged circular jet
Posts: n/a
There may not be a steady-state solution - kind of like the vonKaraman vortices shed from a flagpole. Have you tried a transient solution with few sweeps (~50) per time step? Also, you didn't say whether it simply doesn't converge of if earexe.exe crashes, which sometimes happens if the solution is highly unstable and generates math errors (I see that a lot).

If earexe.exe is not crashing, you can change relaxations on-the-fly while earexe.exe is running and see if the changes affect the convergence rate.
  Reply With Quote


Thread Tools
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 On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Submerged Body Matt Main CFD Forum 2 February 10, 2009 07:15
Horizontal submerged jets B.B. Morales CFX 3 August 28, 2007 18:24
Flooding of submerged body sam FLUENT 0 July 23, 2003 10:46
jets- confined /submerged Gangopadhyay Main CFD Forum 3 August 25, 2000 03:46
Submerged Jet X. Wang Main CFD Forum 2 January 15, 1999 02:44

All times are GMT -4. The time now is 13:45.