Learning Forum

[dkmenend]

Hello,

I am running a 2d invicid case with all walls (no inlet or outlet). The cell size is a 0.05mm and the tube length is 100m, height is 20mm. The left 20mm of the tube is patched to have all hydrogen, the remaining 80mm to the right is patched to have a mole frac of 0.11 and 0.89 of h2 and o2 repsectively. I am using volumetric species transport model 1 step reaction with stiff chmeistry solver default settings. 

I calculated CFL to be 0.02 based off a previous study in which the shock velocity was 1km/s. My time step is 1e-9s and cell length is 0.05mm

I am getting very bad convergence pictured below. I do not know what is causing this. An additional problem is that the contour map of mass fraction of h2 does not change as time goes on. I would expect this to change as reaction rate clearly shows a reaction occouring.

[dkmenend]

I forgot to include that the left side was patched to 100,000pa as well. Also the picture of the mass fraction of h2 did not upload correctly so i have placed it here. 

Another piece of information is that I get the "divergence detected, reducing courant number to 0.002" at each interation as well as the 

"corrections zeroed in 1468 cells due to excessive temperature change"

[Prashanth E]

Hello: Are you able to converge the solution without species and reactions enabled, say with just high and low pressure hydrogen in shock tube?