Staggered time discretization

Katt · February 11, 2019, 09:57

Hi,

I am reading the following paper:
http://gfs.sourceforge.net/papers/tension.pdf

In this paper, the temporal discretization is said to be staggered in time and the discretised form of the fig1. is as in fig2.

Can anyone explain what is this staggered time discretization? Is it splitting one step into two parts? n-> n+0.5 -> n+1?

Thanks.

LuckyTran · February 11, 2019, 11:06

Don't get stuck on semantics because people write whatever they feel like. If you want to know what something is supposed to means then you go ask the original author, because it means something different to everyone.

The good news is, fig2 provides exactly what they mean.

It doesn't mean splitting of time-step into two parts, because that would just be two time-steps. What is particular here is the choice of taking the density, pressure, viscosity, and so on at the intermediate n+1/2 time-step and not at 0 or 1 so that your properties are evaluated at a different time than the solution field for velocity (hence stagger). At least, that's how I interpret it. Otherwise, I wouldn't call it stagger.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
courant number increases to rather large values	6863523	OpenFOAM Running, Solving & CFD	22	July 5, 2023 23:48
simpleFoam error - "Floating point exception"	mbcx4jc2	OpenFOAM Running, Solving & CFD	12	August 4, 2015 02:20
Help for the small implementation in turbulence model	shipman	OpenFOAM Programming & Development	25	March 19, 2014 10:08
same geometry,structured and unstructured mesh,different behaviour.	sharonyue	OpenFOAM Running, Solving & CFD	13	January 2, 2013 22:40
plot over time	fferroni	OpenFOAM Post-Processing	7	June 8, 2012 07:56

February 11, 2019, 11:06		#2
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,673 Rep Power: 65	Don't get stuck on semantics because people write whatever they feel like. If you want to know what something is supposed to means then you go ask the original author, because it means something different to everyone. The good news is, fig2 provides exactly what they mean. It doesn't mean splitting of time-step into two parts, because that would just be two time-steps. What is particular here is the choice of taking the density, pressure, viscosity, and so on at the intermediate n+1/2 time-step and not at 0 or 1 so that your properties are evaluated at a different time than the solution field for velocity (hence stagger). At least, that's how I interpret it. Otherwise, I wouldn't call it stagger.