NickFL
What V.V. says is excellent. I would also add in that obtaining a solution in only 2000 iterations might be unrealistic with a poor initial solution. What we need to do is give it something that is closer to the true solution so that it doesn't have to work so hard. This is where using a 2D model can be helpful in finding the solution conditions. It will also allow you to find regions of high gradients so that you can create a higher mesh density in these regions. Also having your cells in the wrong area can cause the solution to oscillate and by using the 1st order discretization will add dissipation pushing the solution towards the solution basin.
Geometrically this is not a complex model, but the physics make the modeling difficult. Typically these are the models that you have to "babysit" during the solution process. That means run a few hunderd iterations, SAVE, see what the solution looks like, decide whether to adjust the relaxation factors or go back to the last saved solution. This kind of iterative process allows us engineers to look busy :)
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