EFECTOS DE ESCALA EN HEAVE PLATES PARA PLATAFORMAS DE AEROGENERADORES

FLOTANTES

ETSIN – UPM- 2017/Noviembre

Ana Bezunartea, Sergio Fernández Ruano, Adolfo Marón,

Francisco Moreno, José Rios, CEHIPAR, Madrid, Spain

Carlos Lopez Pavon,

COREMARINE, Madrid, Spain,

Antonio Souto-Iglesias, Universidad Politécnica de Madrid, CEHINAV, DMFPA, ETSIN,

Motivation: 1. FOWTS are a promising electric power renewable

source. 2. Semi-submersible concept has good features (onshore

assembling, well-known mooring, small motions if properly designed)

3. In order to minimize heave motions, heave plates are attached to the column base (they modify heave natural period and damping properties).

4. Accurate added mass & damping coefficients are necessary to have accurate time domain simulations for mooring design (difficult for CFD and Freq.D)

5. These coefficients are predicted using model scale tests for which uncertainties due to scaling procedures may arise.

Objective Investigate scale effects on heave plates for

semi-submersible FOWTs

Method Make experiments with especimens of

various scales 1:20, 1:27, 1:45 and compare coefficients

Case study: 1.7Mw

(fp7 hiprwind prj geo.) draft: 15.5m

dist. columns: 35m disc diameter: 20m

h/r=1.53 disf/leg: 663t

column diameter=7m

model / scales =1:20, 27, 45

experimental setup

CEHIPAR

experimental setup

physical problem

Forces (Sarkpaya&Isaacson,1981)

=Theoretical Added Mass

TEST MATRIX KC ≈ 0.15, 0.3, 0.6 - w/w1= 1-3

w1=platform heave resonance freq.

Results (added mass)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0.800 1.300 1.800 2.300 2.800 3.300w/wr

Ca

KC = 0.157 Escala = 20

KC = 0.314 Escala = 20

KC = 0.628 Escala = 20

KC = 0.157 Escala = 27.6

KC = 0.314 Escala = 27.6

KC = 0.628 Escala = 27.6

KC = 0.157 Escala = 45.45

KC = 0.314 Escala = 45.45

KC = 0.628 Escala = 45.45

Results (damping)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.8 1.3 1.8 2.3 2.8 3.3w/wr

Cb

KC = 0.157 Escala = 20

KC = 0.314 Escala = 20

KC = 0.628 Escala = 20

KC = 0.157 Escala = 27.6

KC = 0.314 Escala = 27.6

KC = 0.628 Escala = 27.6

KC = 0.157 Escala = 45.45

KC = 0.314 Escala = 45.45

KC = 0.628 Escala = 45.45

Moreno et al., ISOPE, 2015, 1:80 vs 1:20

Conclusions 1. Experiments with various scale solid heave plates 2. Forces measured and hydrodynamic coefficients

computed 3. KC, w dependency discussed 4. Scale effects seem less important than KC effects

adsfasd

Future work 1. Conduct flow measurements. 2. Use realistic heave plates (with flaps and

reinforcements)

Thank you

Ana Bezunartea, Sergio Fdez, Adolfo Marón,

Francisco Moreno, José Rios, CEHIPAR, Madrid, Spain

Carlos Lopez Pavon,

COREMARINE, Madrid, Spain,

Antonio Souto-Iglesias, Universidad Politécnica de Madrid, CEHINAV, DMFPA, ETSIN,

16

Madrid, Spain June 17-22, 2018

37th International Conference on Ocean, Offshore and Arctic Engineering (OMAE 2018)