Adjusting the Skewness Neighbouring Coupling

hellsblade.91 · January 20, 2018, 15:59

In Ansys Fluent how does turning the skewness neighbouring coupling in pressure vel coupling solver help in getting the residuals converged and in the results

LuckyTran · January 22, 2018, 19:46

The skewness-neighbor coupling check button makes PISO a little more robust and less likely to diverge but it adds a bit more computation than un-checking the box. What this option does is performs an extra skewness correction before doing the neighbor correction.

With PISO is really tough to predict perfomance over all flows. In some cases you can get there faster/slower with different amounts of skewness corrections and neighbor corrections. Doing more corrections increases accuracy but each correction also costs computation time so that it's hard to say if it is better/worse to do more/less. And you have to decide whether it's worth it to do more skewness/neighbor corrections or just give up and do another whole outer iteration.

If you really want to know the answer, then test it yourself on your problem and do your own benchmarking.

January 20, 2018, 15:59	Adjusting the Skewness Neighbouring Coupling	#1
hellsblade.91 Member Hells Blade Join Date: Nov 2017 Posts: 61 Rep Power: 8	In Ansys Fluent how does turning the skewness neighbouring coupling in pressure vel coupling solver help in getting the residuals converged and in the results

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January 22, 2018, 19:46		#2
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,674 Rep Power: 65	The skewness-neighbor coupling check button makes PISO a little more robust and less likely to diverge but it adds a bit more computation than un-checking the box. What this option does is performs an extra skewness correction before doing the neighbor correction. With PISO is really tough to predict perfomance over all flows. In some cases you can get there faster/slower with different amounts of skewness corrections and neighbor corrections. Doing more corrections increases accuracy but each correction also costs computation time so that it's hard to say if it is better/worse to do more/less. And you have to decide whether it's worth it to do more skewness/neighbor corrections or just give up and do another whole outer iteration. If you really want to know the answer, then test it yourself on your problem and do your own benchmarking.