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July 25, 2005, 21:31 |
Help:Finding sources of error
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#1 |
Guest
Posts: n/a
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Hi,
I've written a NS FVM solver. I'm using Ghia's lid driven cavity result to test for accuracy. The u values for the same grid size typically have difference of less than 2%, except one which is different by 20% (0.003 vs 0.004). However, the v values typically have difference of 2-5%. I'm wondering if that is acceptable... I'm trying to find out the source of error. I was thinking of wrong implementation of BC but then my u values will not be so close then. Hence I suspect that there are some careless mistakes in my v,y BC. Is that logical since my v values differs by 2-5%? Thank you very much |
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July 26, 2005, 10:00 |
Re: Help:Finding sources of error
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#2 |
Guest
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Firstly, if You would like to get help here, please give description of Your solver.
NS FVM solver rather wide formulation When I had the same problem, I fixed it having found a mistake in high-order discretization schemes of convective terms (there was a bug). With BC there have not to be problems U and V all zero except upper wall where U=1. As a rule on the fine grid (300x300) with HLPA scheme You should obtain excellent results All that from my experience with SIMPLE solver on staggered as well as colocated grids |
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July 26, 2005, 10:03 |
Re: Help:Finding sources of error
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#3 |
Guest
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By the way, how do You get Ghia's velosity distribution?
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August 2, 2005, 04:29 |
Re: Help:Finding sources of error
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#4 |
Guest
Posts: n/a
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what do you mean by how to get Ghia's velosity distribution?
the velocities are given in his paper in journal of computational physics 1982 48 p387 |
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