Download validation of the cfd code neptune for a full scale simulator for decay

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NEPTUNE CFD MODELING OF PERSEO FACILITY
Figure 5.34: Water volume fraction (top), pressure (middle) and vertical component of
steam velocity (bottom) for t1 = 50.6804 s (left) and t1 = 51.8309 s (right) on a section
at x=3.312
both sides. The mesh has now 129338 hexahedral cells. With the second mesh the
simulation starts at time t0 = 451 s, that is before the increase of the steam mass flow
at the inlet takes place. The simulation appears to be more stable than with the first
mesh, but a few changes were required in the user defined functions in order to run
the simulation up to t1 = 60 s. More particularly, in the drag model usdrag.F the
water characteristic diameter was set to d1 = 5 · 10−5 when the water volume fraction