Staggered time discretization

Katt · February 11, 2019, 10:57

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, 12:06

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.

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February 11, 2019, 12:06		#2
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,762 Rep Power: 66	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.