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The mesh of 2D models is swept in the z-direction with a width of 0.1m (lengthxheightxwidth(x*y*z) = 0.2*1*0.1), and a mesh interval size of 0.002m (#intervals=50), which is in the same order of magnitude as that of x and y directions.
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Results and Discussion
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Since the finer mesh contains 1,500,000 cells, which is 50 times as many as that of the 2D mesh and 70 times as big as the 2D mesh in terms of the file size, the iteration takes about 30 seconds per step. After about 3000 iterations for 30 hours, the residual plots showed a promising tend to fall below a satisfactory level. (The simulations is still running at this moment)
The plot of the residual of
Energy dissipation contour of 2D model, k-epsilon realizable 1.5b
Energy dissipation contour of 3D model with periodic boundary condition, k-epsilon realizable
Since there is no variation in the z-direction in 3D model, the results from 2D is completely duplicated, which agrees with the underlying simplification of 2D simulation.
An important lesson
In FLUENT, the material property, in this case water liquid should be defined in the boundary conditions as well as in the material list. The default material in FLUENT is always air, which need to be checked and modified correctly before every simulation.
started to oscillating with no further trend of convergence. The residual of continuity stays a little above e-5 and the others between e-6 and e-5.
Shown below are the residual plot, energy dissipation contour of various rendering surface and the pathline in mid-width plane and the whole domain.
The solution were not converged enough for the flow to be fully developed. As demonstrated in a simulation later this semester, the contour of energy dissipation rate is quite sensitive to the convergence rate, thus nothing conclusive could be drawn from the solution.
To improve convergence, we can try modifying the mesh to reduce the number of cells in stagnation regionReport summary is a very good way to keep track of all the parameter settings. And more effective and efficient way of data management is necessary for carry out simulation experiments efficiently.