CFD Online Logo CFD Online URL
Home > Forums > General Forums > Main CFD Forum


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

LinkBack Thread Tools Search this Thread Display Modes
Old   March 11, 2005, 12:16
Default Time-Accurate
Posts: n/a
Several weeks ago, there was a discussion here about the time accurate simulation. One of the people said that using pseudo-time approach, faster convergence to steady state is possible. If this is the case, why should we care about physical time step (which is missing in this method)? And, as such, what is the benefit of the time accurate approach?
  Reply With Quote

Old   March 11, 2005, 14:39
Default Re: Time-Accurate
Posts: n/a
Why should we care about the physical time step? For steady-state simulations we don't.

Time accurate computation, as the term suggests, will give you a solution for the time history of the flow, starting from an initial condition. If done right, the solution will be 'accurate' at any time, from the first to the last time step in your computation. In this case we are not only looking for a final solution, but the full evolution of the flow is of interest.

A steady-state solution can be considered a solution for t->infinity, or in some periodic cases as an approximate 'time-averaged' solution. The path that leads to that solution is irrelevant. The solution has to be accurate in the end only, not at every iteration step, as the evolution of the flow is not of interest in the steady-state computation.

There are many methods that can be applied. Pseudo-time iteration is applicable to both steady-state and unsteady computations.
  Reply With Quote

Old   March 11, 2005, 15:00
Default Re: Time-Accurate
amol palekar
Posts: n/a
Just to add on Mani's reply.. For unsteady computations, when one uses dual time stepping algorithm, the time based term (outer loop) is added as a source term and residual is driven to zero (inner loop). So pseudo-time iteration in this case is applicable for the inner loop.
  Reply With Quote


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
Multiple floating objects CKH OpenFOAM Running, Solving & CFD 14 February 20, 2019 09:08
PostChannel maka OpenFOAM Post-Processing 5 July 22, 2009 09:15
Differences between serial and parallel runs carsten OpenFOAM Bugs 11 September 12, 2008 11:16
time accurate solution student Main CFD Forum 2 December 20, 2004 15:34
about convergence of time accurate in CFL3d stone_gargoly Main CFD Forum 0 March 20, 2003 20:22

All times are GMT -4. The time now is 23:58.