Temporal discretisation of spatial derivatives in pisoFoam - Implicit or Explicit?

HakikiCanakkaleli · May 29, 2014, 14:42

Hi

==1==
I have always supposed that temporal discretisation of spatial derivatives in pisoFoam is implicit.

I have, however, realized that, the spatial derivatives are solved in an explicit manner if I correctly understood the following term:

==2==
In the standard pisoFoam of OF version 2.2.x:

Code:

solve( UEqn == -fvc::grad(p) )

==3==
I would really appreciate any comments on this.

Many thanks.

ngj · May 29, 2014, 15:55

Hallo,

It is only the pressure gradient, which is explicit in that line of code. pisoFoam applies a segregated approach to the pressure-velocity coupling, so the pressure cannot be treated implicitly in an equation for the velocity.

Kind regards,

Niels

May 29, 2014, 14:42	Temporal discretisation of spatial derivatives in pisoFoam - Implicit or Explicit?	#1
HakikiCanakkaleli Senior Member Canakkale Dardanelspor Join Date: Aug 2012 Posts: 135 Rep Power: 13	Hi ==1== I have always supposed that temporal discretisation of spatial derivatives in pisoFoam is implicit. I have, however, realized that, the spatial derivatives are solved in an explicit manner if I correctly understood the following term: ==2== In the standard pisoFoam of OF version 2.2.x: Code: solve( UEqn == -fvc::grad(p) ) ==3== I would really appreciate any comments on this. Many thanks.

May 29, 2014, 15:55		#2
ngj Senior Member Niels Gjoel Jacobsen Join Date: Mar 2009 Location: Copenhagen, Denmark Posts: 1,900 Rep Power: 37	Hallo, It is only the pressure gradient, which is explicit in that line of code. pisoFoam applies a segregated approach to the pressure-velocity coupling, so the pressure cannot be treated implicitly in an equation for the velocity. Kind regards, Niels HakikiCanakkaleli likes this. __________________ Please note that I do not use the Friend-feature, so do not be offended, if I do not accept a request.

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