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newtons method failing to converge... help?

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Old   January 27, 2010, 13:11
Question newtons method failing to converge... help?
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Jake Mealy
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Hi,

I want to simulate the flow of oxygen dissolved in water through a porous medium with the aim of determining the change in concebtration of O2 over time. at the moment i am using a homogenous binary mixture of O2 and H20. however the solver wont complete and gives an error saying that newton's method failed to converge in 150 iterations in relation to the variable static pressure. this occurs in all domains. any ideas on why this might be happening? any help would be greatly appreciated.

Cheers.
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Old   January 27, 2010, 14:15
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correction: that should be variable composition mixture.

same problem though
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Old   January 27, 2010, 17:04
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Glenn Horrocks
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It is not going to be possible to debug a multi-phase simulation like this on the forum. All I can recommend is you follow the general principle of starting with a simple single phase flow and making sure everything converges. The add the physics one step at a time, making sure it converges each time.

You may need a very small time step, double precision, a better initial guess or to ramp the flow from a simple initial condition to the true situation.
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