Revised fuzzy control algorithm used in computational fluid dynamic simulation

A revised fuzzy control algorithm was developed to accelerate iteration convergence in numerical fluid dynamic simulation by adjusting the value of the under-relaxation factor. The averaged relative change of the dependent variables between two successive iterations and the variation of this averaged change were selected as two input variables. The increment of the relaxation factor was used as output variable. The control rules were devised according to the fuzzy logic theory and experience, and improved by the numerical practice. The algorithm was tested by four benchmark problems. The results show that the convergence of the revised algorithm is significantly accelerated in all cases considered.