fatal linear solver overflow

h.mortezaee · July 2, 2015, 07:30

hi everyone
im modelling a closed enclosure with cylindrical shape with 7 atm nitrogen gas inside and 3 energy point source in the middle , my mesh is fine my time step is 1e-5 even when i model it with laminar option i get a fatal linear solution overflow , i dont know why , can anyone help me ?
i can provide more information about the simulation if you wanted ,
thank you

JuPa · July 3, 2015, 09:11

Hi,

1) If it's a closed system how do you know it's 7 atm pressure? Did you set the pressure level information in -> solver control -> advanced options -> pressure level information?

2) Is your source term correct? Have you provided a suitable linearization coefficient? Read up on source term linearization by Suhas Patankar in Numerical Heat and Fluid Flow.

3) How do you know your mesh is fine? This is very subjective.

h.mortezaee · July 3, 2015, 11:35

my mesh statistics are fine , and yes i set pressure level information , problem is solved my initialization was wrong , its now converging and the result are good , thanks rico for your reply

July 2, 2015, 07:30	fatal linear solver overflow	#1
h.mortezaee Member hani mortezaee Join Date: Sep 2014 Posts: 30 Rep Power: 12	hi everyone im modelling a closed enclosure with cylindrical shape with 7 atm nitrogen gas inside and 3 energy point source in the middle , my mesh is fine my time step is 1e-5 even when i model it with laminar option i get a fatal linear solution overflow , i dont know why , can anyone help me ? i can provide more information about the simulation if you wanted , thank you

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July 3, 2015, 09:11		#2
JuPa Senior Member Mr CFD Join Date: Jun 2012 Location: Britain Posts: 361 Rep Power: 15	Hi, 1) If it's a closed system how do you know it's 7 atm pressure? Did you set the pressure level information in -> solver control -> advanced options -> pressure level information? 2) Is your source term correct? Have you provided a suitable linearization coefficient? Read up on source term linearization by Suhas Patankar in Numerical Heat and Fluid Flow. 3) How do you know your mesh is fine? This is very subjective.

July 3, 2015, 11:35		#3
h.mortezaee Member hani mortezaee Join Date: Sep 2014 Posts: 30 Rep Power: 12	my mesh statistics are fine , and yes i set pressure level information , problem is solved my initialization was wrong , its now converging and the result are good , thanks rico for your reply