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3.4  Air-water flow around a Series 60 cargo ship

Author
Stéphane Popinet
Command
gerris3D ship.gfs | gfsview-batch3D closeup.gfv | ppm2mpeg -s 640x480 > closeup.mpg
Version
1.2.0
Required files
ship.gfs (view) (download)
S60-scaled.gts closeup.gfv front.gfv comparison.gfv tank-data.png
Running time
4 days

The geometrical Volume-Of-Fluid (VOF) advection scheme of Gerris is used to simulate the air-water interface around a “Series 60 CB=0.6” ship hull. This hull shape is a classical towing tank test case and several experimental dataset are available (see for example the University of Iowa web site).

The liquid is started impulsively from rest to a Froude number of 0.316 corresponding to one of the towing tank cases. The evolution of the interface is illustrated in Figures 20 and 21. After the initial transients have dissipated (Figure 22), the stationary wave pattern can be compared with the experimental measurements (Figure 23). Adaptivity is used based on the value of vorticity in the liquid only. With the relatively high-resolution used here, damping of the final wave pattern is minimal which illustrates the good energy conservation properties of the overall scheme (but requires a significant amount of CPU time).

Only one half of the flow is simulated. The GfsView parameter file closeup.gfv shows how to setup the “Symmetry” objects to display the full symmetrical flow.


Figure 20: MPEG movie of the interface evolution. The interface is coloured according to elevation. The vertical scale is exagerated by a factor of three.


Figure 21: Interface elevation in stationary regime.


Figure 22: Pressure drag and lift forces on the hull as functions of time.


Figure 23: Interface elevation measured in a towing tank (top-half, University of Iowa dataset) and simulation result (bottom-half). The wave reflection in the experimental data is caused by the lateral wall of the towing tank.


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