First of all, we must make clear what iteration means. Iteration is a typical calculation method of numerical calculation, which is applied to solving equations. In its ideological history, a rough approximate solution was first obtained, and then a recursive formula was used to solve it continuously until the accuracy requirement of the solution was met.

Then, why do you need iterative calculation? Because in principle, you can get an exact solution after listing a set of equations according to a problem, but the problem is: 1. It is very troublesome to solve manually, and most complex equations cannot complete this amount of calculation manually, so computer solving 2 is different from our manual solution. Realizing numerical calculation on computer is another set of mathematical methods (specifically Baidu numerical analysis). For example, if you want x 2+5x+6 = 0, the manual solution process is that you know that the equation can be transformed into (x+2)(x+3)=0, so you solve it, but the computer can't predict logically that it can be transformed into the above equation. His method is to take an interval (including the solution). Given that the interval meets the precision requirements of [- 1.9999999, -2.000000001], you can get-2 by taking a random number in the interval.

The influence on the solution result is that the more iterations, the higher the solution accuracy. But there are two settings in fluent, one is precision setting, and the other is iteration number setting. At the beginning of the calculation, if the accuracy requirement of the solution is met but the set number of iterations is not reached, the iteration will end and will still stop until the set number of iterations does not reach the set accuracy.