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First order simulation better than second order

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Old   May 1, 2012, 12:42
Default First order simulation better than second order
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I am finding that the first order solution is much closer to test than second order. I am using the same convergence criteria (max res 5e-4), same boundary conditions, same fluid, etc. Just changing the convergence order. I start with first order/upwind, then from those results go high resolution on both turbulence and pressure, momentum. First order is within 8% of test torque, and second order is 115% over pedicted torque. Mesh changes definitely affect the first order result, but not second order.

This is all a little concerning, as I don't want to just use first order with a mesh that happens to match test as this serves little purpose in development when without test data.
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