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Water wave impact on rigid walls
Water wave impact on rigid walls
Water wave impact on rigid walls
Water wave impact on rigid walls
Water wave impact on rigid walls
Water wave impact on rigid walls
Water wave impact on rigid walls
Water wave impact on rigid walls
Water wave impact on rigid walls
Water wave impact on rigid walls
Water wave impact on rigid walls
Water wave impact on rigid walls
Water wave impact on rigid walls
Water wave impact on rigid walls
Water wave impact on rigid walls
Water wave impact on rigid walls
Water wave impact on rigid walls
Water wave impact on rigid walls
Water wave impact on rigid walls
Water wave impact on rigid walls
Water wave impact on rigid walls
Water wave impact on rigid walls
Water wave impact on rigid walls
Water wave impact on rigid walls
Water wave impact on rigid walls
Water wave impact on rigid walls
Water wave impact on rigid walls
Water wave impact on rigid walls
Water wave impact on rigid walls
Water wave impact on rigid walls
Water wave impact on rigid walls
Water wave impact on rigid walls
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Water wave impact on rigid walls

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  • 1. Water wave impacton rigid wallsBSc. R. Euser06/11/11
  • 2. Contents● About Femto Egineering● Water wave impacts● Simulating water wave impacts using Radioss SPH
  • 3. About femto engineering
  • 4. Company About Software sales Consultancy Engineering agency, Analysis software FE-analysis offering both consultancy and Training Product optimization software for structural analysis (>25 Support Certification employees) Outsourcing More than 12 years experience in CAE Active in BeNeLux and Ukraine Development of client specific software & customization of Femap & Hyperworks Partner of Siemens
  • 5. Activities
  • 6. Customers
  • 7. Offshore projects
  • 8. Water wave impacts
  • 9. Applications Offshore Piping Coastal Automotive
  • 10. About wave impacts● Wave evolution● Surrounding structures● Wave pressure● Air bubbles (aeration)
  • 11. Wave evolution Crest Air pocket Breaking wave Trough Crest Steepening wave Trough Crest Stable wave Trough
  • 12. Surrounding structures● Shape● Roughness● Stiffness
  • 13. Wave pressure t after Pressure impulse P x= ∫ px , t d t t before Worst case Wave Eye Velocity Pressure Velocity
  • 14. Air bubbles (aeration)Positives:● Pressure reduction● DampingNegatives:● Longer impact duration● Larger impact area t = 0.0 ms t = 3.5 ms “Evolution of the air cavity during a depressurized wave impact.” Lugni et al.
  • 15. Simulating water wave impactsusing Radioss SPH
  • 16. Contents● Radioss CFD methods● Radioss SPH approach● SPH Simulations: ● 2D dam break correlation ● 2D water wave impact on a rigid wall● Conclusions
  • 17. Radioss CFD methods ALE SPH Arbitrary Lagrange Eulerian Smooth Particle Hydrodynamics
  • 18. Radioss SPH approach mj f  x i =∑ j  j f x W  r ij , h j { [    ] 2 3 3 2 r 1 r −  r≤h 2 h 3 3 h 2 hW r , h= 3 1 4 h   3 2− r h hr ≤2 h Law Navier-Stokes Radioss SPH Conservation D D i m =− ∇ u =−i ∑ j u ij ∇ W ij of mass Dt Dt j j Conservation of momentum Du Dt 1 =− ∇ T  D ui Dt j  p pj =−∑ m j i i  j  ij ∇ W ij
  • 19. 2D dam break correlation
  • 20. Load case d 0 =0.15 m v gate=1.5 m/s d =0.018 m d0 d 0.38 m 3.55 m Gate velocity 2 1.5 v [m/s] 1 0.5 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 t [s]
  • 21. Radioss SPH model 30,225 particles d particle =0.002 m
  • 22. Results Pressure [Pa] 0 300 600 900 1200 1500 0.219 s 0.281 s 0.343 s =0.010 0.406 s 0.468 s =0.010
  • 23. 2D water wave impact on a rigid wall
  • 24. Goal Measure the effect of particle size on impact pressure
  • 25. Load cases Wave 1 Wave 2 Acceleration vertical plate Acceleration vertical plate 3 10 2 5 1 a [m/s^2] a [m/s^2] 0 0 -1 0 2 4 6 8 10 12 14 16 18 20 0 2 4 6 8 10 12 14 16 18 20 -5 -2 -3 -10 t [s] t [s] Plate Sensors Plate Sensors 20x20 cm 20x20 cm 15 m 15 m 35 m 15 m
  • 26. Models Model Particle size [m] Particle count R1 0.2 3,750 R2 0.04 93,750 Sensors R3 0.02 375,000 Object Element type Plate SPH Detail A Rigid wall Shell Water SPH Sensors RBE2 Water particles Detail A
  • 27. Impact measurement t after Pressure impulse P x= ∫ px ,t d t t before T1 F sensor Discretization P sensor z=∑ z , T DT T0 hsensor d p Load case T0 [s] T1 [s] DT [s] Time interval Wave 1 11.1 11.7 0.001 Wave 2 8.1 8.4 0.001
  • 28. Results – Wave 1 Total Pressure t = 11.1 s t = 11.4 s t = 11.7 s 1.6E+05 1.4E+05 1.2E+05 1.0E+05 R1 R2 P [Pa] 8.0E+04 R3 6.0E+04 4.0E+04 [m/s] R1 2.0E+04 0.0E+00 11.1 11.2 11.3 11.4 11.5 11.6 11.7 t [s] Pressure Impulse 14 12 R2 10 8 R1 z [m] R2 6 R3 4 2 0 0.0E+00 2.0E+04 4.0E+04 6.0E+04 8.0E+04 1.0E+05 PI [Pa s] R3
  • 29. Results – Wave 2 Total Pressure t = 8.1 s t = 8.3 s t = 8.4 s 7.0E+05 6.0E+05 5.0E+05 4.0E+05 R1 R2 P [Pa] 3.0E+05 R3 2.0E+05 [m/s] R1 1.0E+05 0.0E+00 8.1 8.15 8.2 8.25 8.3 8.35 8.4 t [s] Pressure Impulse 14 R2 12 10 R1 8 R2 z [m] 6 R3 4 2 0 0.0E+00 5.0E+04 1.0E+05 1.5E+05 2.0E+05 PI [Pa s] R3
  • 30. Results discussion● Fluid velocity● Fluid pressure● Total pressure (pressure peaks)● Pressure impulse
  • 31. Conclusions● Wave impacts: ● Wave evolution ● Surrounding structures ● Impact pressure ● Aeration● Radioss SPH simulations: ● 2D Dam Break correlation ● 2D wave impacts
  • 32. molslaan 1112611 rk delftT +31 (0) 15 285 05 80 www.femto.nlF +31 (0) 15 285 05 81 info@femto.nl

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