Comparison of the CFD softwares: Jadim and Fluent with experiments

We will compare the simulations with Fluent and Jadim with the experiments, which are movies of oil and water flow in a certain geometry with and without connectivity.

The valves can not be completely opened in the experiments, therefore we will see if respecting the ratio between the hole area and the total area of the valve will have an impact on the simulations.

$$\rho_{water} /\rho_{oil}$$ (kg/m3) $$\nu_{water} /\nu_{oil}$$ (Pa.s) $$ \sigma_{oil/water} $$ (N/m)
1000; 800 0.001;0.01 0.025

  bottom valve closed bottom valve opened
equilibrium time (s) 36.7 19.3

The first simulation is made without ratio for the valves, here is a comparison between the VOF and level set method with the Jadim software.

$$\rho_{water} /\rho_{oil}$$ (kg/m3)
$$\nu_{water} /\nu_{oil}$$ (Pa.s)
$$ \sigma_{oil/water} $$ (N/m)
mesh size (cells)
mesh size (m)
1000; 800
0.1;1
0.025
70x88
0.35x0.44
VOF method on the left and Levelset method on the right.
 
 
VOF method with fluent (same parameters)
 

We have increase the viscosity 100 times to avoid numerical diffusion near the interface but the VOF method still present a lot of numerical diffusion and therefore does not show a equal equilibrium at the end: the iso-contour of oil volume fraction value of 0.5 is not at the same height at the end. The level set method does not show numerical diffusion and still has some problem on the wall, this problem comes from the code which is still developing currently at the IMFT and was firstly coded for bubbles.

Therefore we will continue the simulations with the level set method and try a geometry with ratio.

The results comparing fluent and jadim with the VOF method are the same on the flow versus time but fluent shows less numerical diffusion.