Water wave impacton rigid wallsBSc. R. Euser06/11/11
Contents●   About Femto Egineering●   Water wave impacts●   Simulating water wave impacts    using Radioss SPH
About femto engineering
Company        About              Software sales        Consultancy  Engineering agency,      Analysis software       FE-a...
Activities
Customers
Offshore projects
Water wave impacts
Applications       Offshore     Piping       Coastal    Automotive
About wave impacts●   Wave evolution●   Surrounding structures●   Wave pressure●   Air bubbles (aeration)
Wave evolution                   Crest                   Air pocket  Breaking wave                     Trough             ...
Surrounding structures●   Shape●   Roughness●   Stiffness
Wave pressure                                      t after     Pressure impulse          P x= ∫ px , t d t            ...
Air bubbles (aeration)Positives:●   Pressure    reduction●   DampingNegatives:●   Longer impact    duration●   Larger impa...
Simulating water wave impactsusing Radioss SPH
Contents●   Radioss CFD methods●   Radioss SPH approach●   SPH Simulations:    ●   2D dam break correlation    ●   2D wate...
Radioss CFD methods            ALE                            SPH   Arbitrary Lagrange Eulerian   Smooth Particle Hydrodyn...
Radioss SPH approach                       mj  f  x i =∑                       j  j                          f x W  ...
2D dam break correlation
Load case                                                                 d 0 =0.15 m                                     ...
Radioss SPH model              30,225 particles          d particle =0.002 m
Results               Pressure [Pa]                               0   300      600    900   1200   1500     0.219 s       ...
2D water wave impact   on a rigid wall
Goal   Measure the effect of particle size on            impact pressure
Load cases                                    Wave 1                                                       Wave 2         ...
Models  Model   Particle size [m]   Particle count   R1           0.2               3,750   R2           0.04             ...
Impact measurement                                      t after Pressure impulse          P x= ∫ px ,t d t            ...
Results – Wave 1                                                                                    Total Pressure  t = 11...
Results – Wave 2                                                                                        Total Pressure   t...
Results discussion●   Fluid velocity●   Fluid pressure●   Total pressure (pressure peaks)●   Pressure impulse
Conclusions●   Wave impacts:    ●   Wave evolution    ●   Surrounding structures    ●   Impact pressure    ●   Aeration●  ...
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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Water wave impact on rigid walls

  1. 1. Water wave impacton rigid wallsBSc. R. Euser06/11/11
  2. 2. Contents● About Femto Egineering● Water wave impacts● Simulating water wave impacts using Radioss SPH
  3. 3. About femto engineering
  4. 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. 5. Activities
  6. 6. Customers
  7. 7. Offshore projects
  8. 8. Water wave impacts
  9. 9. Applications Offshore Piping Coastal Automotive
  10. 10. About wave impacts● Wave evolution● Surrounding structures● Wave pressure● Air bubbles (aeration)
  11. 11. Wave evolution Crest Air pocket Breaking wave Trough Crest Steepening wave Trough Crest Stable wave Trough
  12. 12. Surrounding structures● Shape● Roughness● Stiffness
  13. 13. Wave pressure t after Pressure impulse P x= ∫ px , t d t t before Worst case Wave Eye Velocity Pressure Velocity
  14. 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. 15. Simulating water wave impactsusing Radioss SPH
  16. 16. Contents● Radioss CFD methods● Radioss SPH approach● SPH Simulations: ● 2D dam break correlation ● 2D water wave impact on a rigid wall● Conclusions
  17. 17. Radioss CFD methods ALE SPH Arbitrary Lagrange Eulerian Smooth Particle Hydrodynamics
  18. 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. 19. 2D dam break correlation
  20. 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. 21. Radioss SPH model 30,225 particles d particle =0.002 m
  22. 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. 23. 2D water wave impact on a rigid wall
  24. 24. Goal Measure the effect of particle size on impact pressure
  25. 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. 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. 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. 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. 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. 30. Results discussion● Fluid velocity● Fluid pressure● Total pressure (pressure peaks)● Pressure impulse
  31. 31. Conclusions● Wave impacts: ● Wave evolution ● Surrounding structures ● Impact pressure ● Aeration● Radioss SPH simulations: ● 2D Dam Break correlation ● 2D wave impacts
  32. 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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