[FluidKo]

Hello everybody~!

I've learned PIMPLE algorithm by using 'An Introduction to Computational Fluid Dynamics' that is written by H K Versteeg and W Malalasekera.

What I know is that PIMPLE algorithm is composed by momentum prediction and pressure correction.
Although PIMPLE algorithm carries out many processes of pressure correction (inner loop), if residual is still high, then PIMPLE algorithm carries out momentum prediction(outer loop) again.

I've seen some code that includes tolerance in solvers part and tolerance of residualControl in PIMPLE part.

I've heard tolerance in solvers part is related to final residual and tolerance in initial residual is related to initial residual.

But I have no idea what are the initial residual and final residual in uploaded picture.
Which one does initial residual and final residual represent?

Thank you~!