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Re: [Question #699072]: About the examples/ThermalEngine


Question #699072 on Yade changed:

Ziyu Wang gave more information on the question:
Hello Robert!
I have the latest findings, which may help solve this problem:

I follow your suggestion and consider changing  O.dt and the number of
spheres respectively.I found something interesting..

1.I have tried the number of spheres as 100,200,300,500,1000,2000,and the O.dt as 1e-4 to 1e-6 (I also tried using the O.dt=PWaveTimeStep(), not sure if it's appropriate).The success of the simulation does not seem to have much to do with O.dt but O.dt affects the speed of the simulation(The premise is that the simulation is successful, that is, there is temperature instead of Nan)
2.As described in 1, I found that when the number of spheres is 100,200,1000,2000, the simulation is successful (i.e. the pore and body have their own temperature rather than Nan).But 300,500,the problem still exists,like the original script (unchanged).With these scripts,there is a same warning:
CHOLMOD warning: matrix not positive definite. file: ../Supernodal/t_cholmod_super_numeric.c line: 911
(Maybe this is the reason of problem?)
3.As mentioned in 2, even in the successful cases, the curves are different.In the example script, I guess the ideal curve should be to keep the pore temperature at 343.15 and gradually increase the particle temperature from 333.15 to 343.15.If I'm right, this is true only when num = 100, and in other cases, the body temperature will increase to 353.15..
What is wrong with the problem?

Best regards.

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