几个名词什么区别

happyking

what's the diffrence between "time step"and the"iteration step"
thanks a lot

kpxx666

time step is used in unsteady flow simulation. it is the time interval. the iteration step is used to soving the matrix equations when you use iteration method. For example, if you use the implicite method to solve the unsteady flow problem, in each time step, you get a matrix which need to be solved. I this case, maybe a lot of iteration step needed to get convergent solution of it.
If you use the insteady method to solve the steady flow, that means time tends to be infinite. In this case, the time step and iteration step is similar. Actually, it may be the same.
If you solve the steady flow problem directly, no time step involved. Only the concept of the iteration step is used because you just sove a matrix.

boling2000

time step 是不是指时间步长？
iteration step 是迭代步数？

junior

At many cases, they are the same thing. The time step usually can be pseudo time step when you try to resolve a steady problem with unsteady method. The so-called iteration steps is actually how many steps you are approaching your final result. As in many cases, if not all cases, the numerical solution is obtained in a iterating manner, so, you can take these two words as the same thing, it does not make any difference, unless you are preparing to publish a normal paper.