# How to accelerate a time-dependent algorithm to steady-state?

 User Name Remember Me Password
 Register Blogs Members List Search Today's Posts Mark Forums Read

 October 13, 1998, 17:55 How to accelerate a time-dependent algorithm to steady-state? #1 Matthew Cordery Guest   Posts: n/a I am wondering how people go about accelerating a time-dependent algorithm to steady-state? I am particularly interested in the situation where one is solving the time-dependent Stokes problem without the non-linear terms. I've been considering using the algorithm of Zienkiewicz et al (Int. J. Numer. Eng., v43, p565-583) but am only interested in the steady state solution (sans advection of the mesh after the velocities are found). Matthew

 October 15, 1998, 09:05 Re: How to accelerate a time-dependent algorithm to steady-state? #2 John C. Chien Guest   Posts: n/a It's hard to answer because you have to make sure that your unsteady algorithm , your mesh and your boundary conditions will give you a steady state solution in the first place. Most of the time, the unsteady solution remains unsteady just because of the mesh you used. I would say, first run a true unsteady solution first, and make sure that your method and mesh and the boundary conditions will give you a steady state solution. Then, there are two general approach you can use: 1) fool around with the local time steps, that is to increase it to speed up the real time. 2) spend more time in the area where the solutions have difficulty in convergence. A good initial flow field guess also will reduce the computing time.

 October 19, 1998, 23:32 Re: How to accelerate a time-dependent algorithm to steady-state? #3 G.P. Xia Guest   Posts: n/a Hi, For the convergence acceleration of time-marching algorithm, I think there are three popular methods. Local time stepping(Dual time steeping for unsteady problem), Local Preconditioning and Multigrid all work well. Conbination of two of the three methods will have very dramatical effect. You can read CFD Review 1995', or the papers of Marviplis(NASA Langley).

 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 Niklas Wikstrom (Wikstrom) OpenFOAM Running, Solving & CFD 122 June 15, 2014 06:20 Lord Kelvin OpenFOAM 6 April 12, 2011 11:24 jing113cn FLUENT 2 January 15, 2010 04:18 KJ Larsen FLUENT 0 January 28, 2009 13:00 Lisa Main CFD Forum 11 July 5, 2000 14:37

All times are GMT -4. The time now is 18:25.

 Contact Us - CFD Online - Top