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Applied Computational Fluid Dynamics Techniques - Wiley Episode 2 Part 9

Tham khảo tài liệu 'applied computational fluid dynamics techniques - wiley episode 2 part 9', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | TREATMENT OF FREE SURFACES 447 a b c d Figure 19.13. a - d LNG tanker fleet evolution of the free surface plane and the ship are moved and the Navier-Stokes VOF equations are integrated using the arbitrary Lagrangian-Eulerian frame of reference. The LNG tanks are assumed to be 80 full. This leads to an interesting interaction of the sloshing inside the tanks and the drifting ship. The mesh had approximately nelem 2 670 000 elements and the integration to 3 minutes of real time took 20 hours on a PC 3.2 GHz Intel P4 2 Gbytes RAM Linux OS Intel compiler . Figure 19.12 b shows the evolution of the flowfield and Figures 19.12 c and d the body motion. Note the change in position for the ship as well as the roll motion. 19.2.8.5. Drifting fleet of ships This example shows the use of interface capturing to predict the effects of drift and shielding in waves for a group of ships. The ships are the same LNG tankers as used in the previous example but the tanks are considered full. The boundary conditions and mesh size distribution are similar to the ones used in the previous example. The ships are treated as free floating objects subject to the hydrodynamic forces of the water. The surface nodes of the ships move according to a 6-DOF integration of the rigid-body motion equations. Approximately 30 layers of elements close to the wave-maker plane and the ships are moved and the Navier-Stokes VOF equations are integrated using the arbitrary Lagrangian-Eulerian frame of reference. The mesh had approximately 10 million elements and the 448 APPLIED COMPUTATIONAL FLUID DYNAMICS TECHNIQUES integration to 6 minutes of real time took 10 hours on an SGI Altix using six processors 1.5 GHz Intel Itanium II 8 Gbytes RAM Linux OS Intel compiler . Figures 19.13 a - d show the evolution of the flowfield and the position of the ships. Note how the ships in the back are largely unaffected by the waves as they are blocked by the ships in front and how these ships cluster together due to wave