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Old   July 27, 2005, 09:27
Default convergency problem
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enis
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I hope someone can help me about my problem written below;

What would be reason if all computations are converging to a different level of value at the outlet regardless of what input values are given as inlet boundary conditions. i mean, changing inlet conditions seems to have not any effect in the flow of the computational domain. (I tested a benchmark problem of Ransom's "water faucet problem" and got reasonably good results as in the literature, however it was a 1-D problem)

my simulation parameters: -two-fluid model -both phases are assumed incompressible, -3-D cylindrical dimensions, -1 inlet 1 outlet in radial directions, -horizontal flow,

inlet boundary : a prescribed value is given to radial velocity and volume fractions. pressure is extrapolated from adjacent inlet cell.

outlet boundary: continuative outflow boundary conditions for velocity, volume fractions and pressure (all are extrapolated from adjacent inlet cell values).

Changing the number of cells, decreasing time step sizes made no improvements in my runs.

if anybody can help, i would be very grateful,

thanks a lot,

P.S.: i imposed periodic boundary condition for start and end cells in angular directions as Jim Park recommended.
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