# Segregated or coupled?

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

 September 23, 2000, 04:38 Segregated or coupled? #1 Pierluigi Allegro Guest   Posts: n/a Sponsored Links Hi All, I'm solving a steady 3d axial flow turbine problem using standard k-eps model. The balde is film-cooled by 3 cooling holes; fluid is rotatind at 314rad/s (399m/s in the middle) and the higher Ma is 0.88. The problem is that in the compressible simulation the segregated solver diverges for any relax factor, so I have too use the coupled solvet that takes a lot of time ( I have 500.000 nodes). Is it possible to use the segregated solver or the problem prevent this? Thankyou all.

 September 23, 2000, 13:16 Re: Segregated or coupled? #2 John C. Chien Guest   Posts: n/a (1). All I know is, for subsonic flow it is better to use pressure-based formulation. (2). Since your problem is in the transonic range, the right approach is the density-based transient formulation. I am somewhat confused with their new names of algorithm. (3). So, ths suggestion is: use the density-based transient formulation. Based on my previous experience, it may take more than a couple of weeks to converge using compressible, transient formulation. But, that is life. (4). Even if you can obtain the solution ,500,000 nodes may not be adequate at all for mesh independent solution.

 September 25, 2000, 23:51 Re: Segregated or coupled? #3 Jin-Wook LEE Guest   Posts: n/a Dear Pierluigi Allegro In Fluent, coupled solver means 'algorithm for compressible flow'. It is better for you to use 'coupled solver' because compressible effect can't be neglected for your problem, Mach Number =0.88. In general, as you may know, the flow is considered as compressible when Ma>0.3. Sincerely, Jinwook

 Thread Tools Display Modes Linear Mode

 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 OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post hamzamotiwala STAR-CCM+ 7 October 25, 2011 19:35 naomi FLUENT 4 August 2, 2007 06:47 Oz FLUENT 2 November 8, 2006 17:02 Amit Shrestha FLUENT 1 November 19, 2005 04:24 Nori FLUENT 0 September 29, 2005 14:24