Convergence Monitoring

August 8, 2005, 10:40

Hi All,

With iterative time advancement I can watch convergence of a flow property (e.g. velocity) at a point on a per-iteration basis.

Does anyone know how to do this with non-iterative time advancement (NITA)? I only seem to be able to get a report of the residual after each time step and have no idea what it is doing within the time step itself.

Cheers, Jim.

soheil_r7 · August 22, 2005, 20:09

With the NITA schemes with either Fractional-Step or PISO scheme, there's no need for the inner iterations (velocity-pressure), hence the name NITA.That's why FLUENT report the resiudals only after each time-step. Yet the NITA schemes preserve the second-order accuracy. The only iterations being done behind the scene are for the individual linearized equations and for the coupled (and non-linear)momentum equations.

August 25, 2005, 13:49

hi helper how to apply this procedure and also do u know about the variable time stepping procedure. thank u in advance bye

August 8, 2005, 10:40	Convergence Monitoring	#1
Jim Guest Posts: n/a	Hi All, With iterative time advancement I can watch convergence of a flow property (e.g. velocity) at a point on a per-iteration basis. Does anyone know how to do this with non-iterative time advancement (NITA)? I only seem to be able to get a report of the residual after each time step and have no idea what it is doing within the time step itself. Cheers, Jim.

August 22, 2005, 20:09	Re: Convergence Monitoring	#2
helper Guest Posts: n/a	With the NITA schemes with either Fractional-Step or PISO scheme, there's no need for the inner iterations (velocity-pressure), hence the name NITA.That's why FLUENT report the resiudals only after each time-step. Yet the NITA schemes preserve the second-order accuracy. The only iterations being done behind the scene are for the individual linearized equations and for the coupled (and non-linear)momentum equations. soheil_r7 likes this.

August 25, 2005, 13:49	Re: Convergence Monitoring	#3
satya Guest Posts: n/a	hi helper how to apply this procedure and also do u know about the variable time stepping procedure. thank u in advance bye

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