When artificial diffusion terms are introduced in two-fluid model, the effects of different artificial diffusion coefficients are studied. For vertical pipe Water Faucet problem, when the artificial diffusion coefficients are gradually increased, nonphysical oscillations can be eliminated. For horizontal pipe flow in ill-posed region, the calculated results without diffusion terms agree with experimental data but the mesh independent solution cannot be obtained. When the coefficients calibrated in Water Faucet problem are adopted, hydrodynamic instability is suppressed to some extent and slug frequency is underestimated. Therefore, the amount of artificial diffusion varies with different flow conditions and should be determined specially.
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