Why my simulation often terminate earlier than it is supposed to last?
 

Hi all,

I am new to CFD and I am trying to simulate the flow of water in an irrigation systems. The problem I have is that my simulation often terminates much earlier than it should be. For example, I often set the finish time to 20 seconds. but the simulation may only last for 4 seconds. Can you please help me to find what the potential problems are? Many thanks. This problem has bothered me for many days.

All the best,
Andrew

Error message?
 

What error message do you get when your simulation terminates?

Hi Светлана,

Thanks you so much for replying my thread. Strangely enough, although this problem occurred to me many times recently, I did not encounter one today. I'll let you know what the error message is when it occurs again. Спасибо большое!

Best,
Andrew

Hi Светлана,

I met the problem again. Below is the error message. I set the finish time to 40 seconds, but the simulation in fact only lasted for less than 2 second. Can you please help me figure out the cause of this problem? Many thanks.

Best,
Andrew


Solver Messages:

convective flux exceeded stability limit
at t= 1.1662E-01 cycle= 1 iter= 1 delt= 1.1662E-01 mesh block 1
restarting cycle with smaller time step
maximum failure ratio = 1.54505E+01 is in y-coordinate direction
at cell ( 147, 404, 20) mesh block 1


*** time-step size < dtmin ***

delt = 3.99776E-06 dtmin = 4.00000E-06
(see solver summary file hd3out for details)