Altair Conf 2011 R Euser

7/27/2019 Altair Conf 2011 R Euser

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06/11/11

Water wave impact

on rigid walls

BSc. R. Euser


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Contents

About Femto Egineering

Water wave impacts

Simulating water wave impactsusing Radioss SPH


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About femto engineering


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Company

About Software sales Consultancy

Engineering agency,offering both

consultancy andsoftware for structural

analysis (>25

employees)

More than 12 yearsexperience in CAEActive in BeNeLux

and Ukraine

Development of clientspecific software &

customization ofFemap & Hyperworks

Partner of Siemens

Analysis software

Training

Support

FE-analysis

Product optimization

Certification

Outsourcing


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Activities


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Customers


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Offshore projects


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Water wave impacts


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Applications

Offshore

Coastal

Piping

Automotive


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About wave impacts

Wave evolution

Surrounding structures Wave pressure

Air bubbles (aeration)


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Wave evolution

Breaking wave

Steepening wave

Stable wave

Crest

Trough

Crest

Air pocket

Trough

Trough

Crest


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Surrounding structures

Shape Roughness

Stiffness


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Wave pressure

Px=tbefore

tafter

px, td t

VelocityPressureVelocity

Wave Eye

Worst case

Pressure impulse


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Air bubbles (aeration)

Positives:

Pressurereduction

Damping

Negatives:

Longer impactduration

Larger impactarea

t = 0.0 ms t = 3.5 ms

Evolution of the air cavity during a depressurized wave impact.Lugni et al.


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Simulating water wave impactsusing Radioss SPH


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Contents

Radioss CFD methods

Radioss SPH approach

SPH Simulations:

2D dam break correlation

2D water wave impact on a rigid wall

Conclusions


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2D dam break correlation


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Load case

3.55 m0.38 m

d

d0

d0=0.15m

d=0.018mvgate=1.5m/s

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

0

0.5

1

1.5

2

Gate velocity

t [s]

v[m/s]

S


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Radioss SPH model

30,225 particles

dparticle=0.002m

R lt


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Results

0.219 s 0.281 s 0.343 s

0.468 s0.406 s

=0.010

=0.010

0 1500300 600 900 1200

Pressure[Pa]
http://movies/Dam_Break_2D_SPH_UHR_c.mpghttp://movies/Dam_Break_2D_SPH_UHR_c.mpghttp://movies/Dam_Break_2D_SPH_UHR_c.mpghttp://movies/Dam_Break_2D_SPH_UHR_c.mpghttp://movies/Dam_Break_2D_SPH_UHR_c.mpghttp://movies/Dam_Break_2D_SPH_UHR_c.mpghttp://movies/Dam_Break_2D_SPH_UHR_c.mpghttp://movies/Dam_Break_2D_SPH_UHR_c.mpg


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2D water wave impacton a rigid wall

G l


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Goal

Measure the effect of particle size onimpact pressure

Load cases


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Load cases

Wave 1 Wave 2

0 2 4 6 8 10 12 14 16 18 20

-10

-5

0

5

10

Acceleration vertical plate

t [s]

a[m/s^2]

0 2 4 6 8 10 12 14 16 18 20

-3

-2

-1

0

1

2

3

Acceleration vertical plate

t [s]

a[m/s^2]

35 m

Sensors20x20 cm

Plate

15 m

15 m

Sensors20x20 cm

Plate

15 m

Models


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Models

Water particles

Detail A

Detail A

Model Particle size [m] Particle count

R1 0.2 3,750

R2 0.04 93,750

R3 0.02 375,000

Object Element type

Plate SPH

Rigid wall Shell

Water SPH

Sensors RBE2

Sensors

Impact measurement


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Impact measurement

Px=tbefore

tafter

px, td tPressure impulse

Psensorz=T0

T1

Fsensorhsensordp

z,TDTDiscretization

Load case T0 [s] T1 [s] DT [s]

Wave 1 11.1 11.7 0.001

Wave 2 8.1 8.4 0.001

Time interval

Results Wave 1


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Results Wave 1

0. 0E+00 2. 0E+04 4. 0E+04 6. 0E+04 8. 0E+04 1. 0E+05

0

2

4

6

8

10

12

14

Pressure Impulse

R1R2

R3

PI [Pa s]

z[m]

11.1 11.2 11.3 11.4 11.5 11.6 11.7

0.0E+00

2.0E+04

4.0E+04

6.0E+04

8.0E+04

1.0E+05

1.2E+05

1.4E+05

1.6E+05

Total Pressure

R1

R2

R3

t [s]

P[Pa]

t = 11.4 s t = 11.7 st = 11.1 s

R1

R2

R3

[m/s]

Results Wave 2
http://movies/W1R3.mpghttp://movies/W1R3.mpghttp://movies/W1R3.mpghttp://movies/W1R3.mpghttp://movies/W1R3.mpg


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Results Wave 2

0.0E+00 5.0E+04 1.0E+05 1.5E+05 2.0E+05

0

2

4

6

8

10

12

14

Pressure Impulse

R1

R2

R3

PI [Pa s]

z[m]

8.1 8.15 8.2 8.25 8.3 8.35 8.4

0.0E+00

1.0E+05

2.0E+05

3.0E+05

4.0E+05

5.0E+05

6.0E+05

7.0E+05

Total Pressure

R1

R2

R3

t [s]

P[Pa]

R1

t = 8.1 s t = 8.3 s t = 8.4 s

R2

R3

[m/s]

Results discussion
http://movies/W2R3.mpghttp://movies/W2R3.mpghttp://movies/W2R3.mpghttp://movies/W2R3.mpg


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Results discussion

Fluid velocity

Fluid pressure Total pressure (pressure peaks)

Pressure impulse

Conclusions


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Conclusions

Wave impacts:

Wave evolution

Surrounding structures

Impact pressure

Aeration

Radioss SPH simulations:

2D Dam Break correlation 2D wave impacts


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molslaan 1112611 rk delftT +31 (0) 15 285 05 80F +31 (0) 15 285 05 81

[email protected]
http://www.femto.nl/http://www.femto.nl/

Altair Conf 2011 R Euser

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