Aalborg Universitet. Wave Forces on Windturbine Foundations Larsen, Brian Juul; Frigaard, Peter Bak. Publication date: 2005

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1 Aalborg Universitet Wave Fores on Windturbine Foundations Larsen, Brian Juul; Frigaard, Peter Bak Publiation date: 5 Doument Version arly version, also known as pre-print Link to publiation from Aalborg University Citation for published version (APA): Larsen, B. J., & Frigaard, P. (5). Wave Fores on Windturbine Foundations: for the London Array. Aalborg: Department of Civil ngineering, Aalborg University. (Hydraulis and Coastal ngineering; No. 3). General rights Copyright and moral rights for the publiations made aessible in the publi portal are retained by the authors and/or other opyright owners and it is a ondition of aessing publiations that users reognise and abide by the legal requirements assoiated with these rights.? Users may download and print one opy of any publiation from the publi portal for the purpose of private study or researh.? You may not further distribute the material or use it for any profit-making ativity or ommerial gain? You may freely distribute the URL identifying the publiation in the publi portal? Take down poliy If you believe that this doument breahes opyright please ontat us at vbn@aub.aau.dk providing details, and we will remove aess to the work immediately and investigate your laim. Downloaded from vbn.aau.dk on: April 5, 17

2 AALBORG UNIVRSITY Wave Fores on Windturbine Foundations for the London Array

3 DPARTMNT OF CIVIL NGINRING AALBORG UNIVRSITY SOHNGAARDSHOLMSVJ 57 DK-9 AALBORG DNMARK TLPHON TLFAX Hydraulis and Coastal ngineering No. 3 ISSN August 5 Wave Fores on Windturbine Foundations for the London Array by Brian Juul Larsen & Peter Frigaard, Aalborg University

4 Wave Fores on Windturbine Foundations for the London Array Contents Page Introdution Tests Saling Desription of Models Desription of Set-up Waves Measurements Test programme Results Appendix 1 - Results Appendix - Models Appendix 3 - CD with movie bits from the tests Bakside 3

5 Wave Fores on Windturbine Foundations for the London Array Introdution By request from COR Ltd. I nergi NS a test programme has been performed to determine the wave fores on two types of foundation for an offshore windturbine. The tested foundation types are a monopile and one. Furthermore the shaft of the one has been tested. For further information on the onduted test programme ontat Brian Juul Larsen (phone: , i5bjl@ivil.aau.dk) or Peter Frigaard (phone: , peter.frigaard@ivil.aau.dk). 4

6 Wave Fores on Windturbine Foundations for the London Array Tests Saling The tests are performed with a length sale of 1:5. All values are saled aording to Froudes modellaw: Length: Time: AL= 5 AT= ALY, = 7.7 All measures in the following report will be in prototype values if nothing else is mentioned. Desription of Models The two types of foundation that are being tested are shown underneath in figure 1. In appendix the models are shown in detail. I I L--- J Figure 1. Monopile and onrete one. The models are made of various types of plasti. 5

7 Desription of Set-up Wave Fores on Windturbine Foundations for the London Array The tests are onduted in a wave flume that is 945 meters long and 75 meters wide, see figure. H [::><: ---') 1:1&,,so >!ode I. --,,s I Pump ":.. \I) Figure. The wave flume. All measures in meters. Waves All tests were made with a JONSW AP spetra. The peak enhanement fator, y, is at all times set at 3.3. The duration of the tests was 3Y h or 13 to waves depending on period. Measurements The wave elevation signal was measured beside the model by means of three wave gauges to separate the inoming and refleted waves by means of the method by Mansard and Funke (1986). The urrent veloity has been measured with an ultrasoni flowmeter. The fores on the monopile are measured with a strain gauge based fore ell that measures fore and moment in three diretions perpendiular to eah other. The fores on the onrete one are measured as two moments in two different heights above the model. As it an be seen fro:n the figures in appendix 1 the wave gauges are mounted slightly in front of the model. (Approximately the quarter of a wave length. The waves peak more or less together with the fores in stead oft/4 after). 6

8 Test programme Wave Fores on Windturbine Foundations for the London Array Test No. Hs [m] Hmo [m] To [m] h [m] U [m/s] Waves Struture F Monopile F Monopile F Monopile F Monopile F Monopile F Monopile F Monopile F Monopile F Monopile F Monopile Fll Monopile F Conrete one F Conrete one F Conrete one F Conrete one F Conrete one Fl Conrete one F Conrete one F Conrete one F Conrete one F Conrete one F Conrete one F Shaft of one F Shaft of one Table 1. Test programme. On the inside of the bakside there is CD attahed with a 1 minute movie lip from eah test. There is also a exe file with the required video ode. The CD also ontains the raw uninterpreted output files from the 4 tests. 7

9 Wave Fores on Windturbine Foundations for the London Array Results Test Hmo Fh,max Fh,min Mmax Mmin No. [m] [kn] [kn] [knm] [knm] F F F F F F F F F F F F F F F F F F F F F F F F Table. Test results. 8

10 Wave Fores on Windturbine Foundations for the London Array Test Hmo Fh,lf5,max Fh,lf5,min Mlt5,max M lf5,min No. [m] [kn] [kn] [knm] [knm] F F F F F F F F F F F F F F F F F F F F F F F F Table 3. 1/5 values. 9

11 Wave Fores on Windturbine Foundations for the London Array 1 9 8,., X 7 6 =.. Monopile h = 9 m X Monopile h = 1 m 11! o Monopile h = 15 m >< lis 5 V one h = 9 m u. 4 X Cone h = 1 m " ov OCone h = 15 m! Hmo [m] Monopile h = 9 m ' 8 X Monopile h = 1 m ox =.. o Monopile h = 15 m >< one h = 9 m lis,., 6 :!: Hmo [m] Figure 3. Fh,max and Mmax as a funtion ofhmo X x one h = 1 m o Cone h = 15 m 1

12 Wave Fores on Windturbine Foundations for the London Array 7 6 5,.. X Monopile h = 9 m... X Monopile h = 1 m '; 4 Cl! o Monopile h = 15 m Cone h = 9 m &() x X Cone h = 1 m u. 1 - X o Cone h = 15 m Hmo [m) 7 ' 6 u 5 :. 4 - X Monopile h = 9 m X Monopile h = 1 m >< O.j o Monopile h = 15 m Cl! &() 3 Cone h = 9 m N x Cone h = 1 m )IX -... :!!: o Cone h = 15 m V 1,... j} Hmo [m) X Figure 4. Fh,I/5,max and M11so,max as a funtion ofhmo 11

13 Wave Fores on Windturbine Foundations for the London Array Appendix 1 - Results FOl With a monopile Hmo =.1 7 m, Tp = 6.5 s, h = 9 m Fh,max = 879 kn Fh,min = -1 kn Mmax = 836 knm Mmin = -734 knm M --eta*1-1 ========== X =:. :.5.D ro rj)... ro -.5 1, : 5 Q..:: ro -5 Sampling No. -1 L i_ L L Fore [kn] Fore [kn] 5 =:. l.l L- W- 1 o x. Prob. [%] ' =: ::: L_=L 1' 1' x. Prob. [%] 1, r============= - - F1 - - JONSWAP N.s i!: ;; : ' t> a. (/) 5 O L----= Frequeny[H] ========== F1 3 --Rayleigh 1 x. Prob. [%] 1

14 Wave Fores on Windturbine Foundations for the London Array F With a monopile Hmo=3.98m,Tp=9.1s,h=9m Fh,max = 1534 kn Fh,min = -193 kn Mmax = 987 knm Mmin = -787 knm.5 X M --eta*1-1 ======== Sa mpling No. ('J (f)... ('J L l_ L :1 u. -1 Fore [kn] Fo re [kn] L x. Prob. [%] -1L x. Prob. [%] 4, r=========== --F..s 3 --JONSWAP "' (f) F Rayleigh Frequeny [H] x. Prob. [%] 13

15 Wave Fores on Windturbine Foundations for the London Array F3 With a monopile Hmo= 5.3m, Tp = ll.7s,h = 9m Fh,max = 6 kn Fh,min = kn Mmax = knm Mmin = knm.5 X M Sampling No. ' x g. CO <I> (/) -CO <I> ::: -1 - L Fore [kn] 1 a....>.:: CO ;::: -5 F MWL -1L _ Fore (kn) 1ooo u <I> x. Prob. [%) x. Prob. [%) "'.s 6.&!- '(i.i : <I> " 4 --F3 --JONSWAP 4 r ========== F3 3 " --Rayle igh n <I>.. (/) J.! Frequeny [H) x. Prob. [%) 14

16 Wave Fores on Windturbine Foundations for the London Array F4 With a monopile Hmo=.1 m, Tp=6.5 s,h = 1m Fh,max = 133 kn Fh,min = kn Mmax = 16 knm Mmin = knm ' X 1 4 =.... < (/) - < Fore [kn] M - - eta*1-1 ========== ::,. <.) < -5 Sampling No. F MWL Fore [kn] =.. u._1 1 o x. Prob. [%] ' = X o 1 o x. Prob. [%] 1 N.s (/) 5 " t5 a. en --F4 - - JQNSWAP./ Frequeny [H] 6 4 "' F4 --Rayleigh 1-1 o x. Prob. [%] 15

17 Wave Fores on Windturbine Foundations for the London Array FOS With a monopile Hmo = 3.95 m, Tp = 9.3 s, h = 1 m Fh,max = 171 kn Fh,min = -137 kn Mmax = 17 knm Mmin = -174 knm --eta*1-1 ======== Sampling No. ' X 1 4 :::s :::::..Cl CO Ql en -CO -: Ql F MWL -: a.. J9 ;:( Fore [kn ] Fore [kn] -1 :::s LL '.5 :::s : Ql -.5 X o 1 o x. Prob. [%] x. Prob. [%] (j) 3 "'. en : Ql " t5 1 Ql a. (f) ) --F5 --JONSWAP Frequeny [H] 4 3 <J) ""'- I F5 --Rayleigh 1 o 1 o x. Prob. [%] 16

18 Wave Fores on Windturbine Foundations for the London Array F6 With a monopile Hmo= 6.1 m, Tp= 11.3 s,h = 1m Fh,max = 3433 kn Fh,min = -191 kn Mmax = 3336 knm Mmin = knm ' X =. ::::. C'O Cl) C/) -C'O - Cl) :: ;1 =. u.. -1 Fore [kn] o- 1 x. Prob. [% ] X M --eta*1 - ========== Sampling No. 1 F MWL a....>.:: u.!9 ;,( -5 ' = Cl) :: X 1 4 Fore [kn] -1 1 o 1 x. Prob. [%] V) N.s C/) Cl) ' C'O.._ <3 Cl). Cl) f d) --F6 --JONSWAP r ========== F6 3 --Rayle igh o 1 o Frequ eny [H] x. Prob. [%] 17

19 F7 Wave Fores on Windturbine Foundations for the London Array X 1 4 With a monopile Hmo =. m, Tp = 6.6 s, h = 15 m F h,max = 17 kn.5 Fh,min = -1 kn Mmax = 156 knm Mmin = knm M - - eta *1-1 ========== X g 5.D ro... <ll.><: <JJ --, Sampl ing No. FO? MWL <U - : <ll -1-5 ::: Fore [kn ] X '. - - <ll : <ll u.. -1 ::: -1 Fo re [kn] o 1 o o 1 o x. Prob. [%] x. Pro b. [%] 1 6 N --F7 FO?.s --JONSWAP --Rayle igh <JJ 4 : "' <ll 5 " ::s <U... t5 <ll a. (j) ) o 1 o Frequeny[H] x. P rob. [%] 18

20 Wave Fores on Windturbine Foundations for the London Array F8 With a monopile Hmo = 3.75 m, Tp = 9.3 s, h = 15 m F h,max = 1681 kn Fh,min = kn Mmax = knm Mmin = knm X M ---eta*1-1 ========== ' g. ro (]) Cl) -ro (]) :: X Fore [kn] Sampling No r===== F MWL.> ro Fore [kn ] :1 (]) -1 ' (]) :: o 1 x. Prob. [%] - 1 o 1 x. Prob. [%] 3 r r============= "' --F8..s --JONSWAP Cl) (]) " 1 (3 (]) a. Cl) t ) L...:..::_=------' Frequeny[H] 4, ===========n F8 3 --Rayleigh... o 1 o x. Prob. [%] 19

21 F9 Wave Fores on Windturbine Foundations for the London Array X 1 4 With a monopile, Hmo=5.67m,Tp=l1.3s,h=l5m Fh,max = 51 kn Fh,min = -197 kn Mmax = 7711 knm Mmin = knm -1 --M ' X :::::.. u <!) (J) (ij <!) -5 --eta* 1 -======== Sampling No. ::: Fore [kn] 4 X 1 4 Fore [kn] <!) u.. '...- <!) ::: - L_ - 1" 1" o- 1 o x. Prob. [%] x. Prob. [%] (ij' 8 4 N --F JONSWAP (J) <!) -o 4 t3 <!). (/) F9 3 --Rayleig h "' Frequeny [H] x. Prob. [%]

22 Wave Fores on Windturbine Foundations for the London Array Fl O With a monopile Hmo =.41 m, Tp = 6.6 s, h = 9 m, U = 1.5 rn/s.5 Fh,max = 1149 kn Fh,min = -867 kn Mmax = 794 knm M Mmin = -911 knm --eta*1-1 ======== ' X :.5 5. (ll... (I) (J) () Sam pl ing No. F MWL (ll (ij -.5 <( -5 (I) :: Fore [kn] Fore [kn] ' LL o o x. Prob. [%] x. Prob. [%] N Vi' 1 6 I == :SWAP I F1.s --Rayleigh 4 U) 5 -o ;s ) u.. (/) (J) o 1 o Frequeny [H] x. Prob. [% ] 1

23 Fll Wave Fores on Windturbine Foundations for the London Array X 1 4 With a monopile Hmo = 5.55 m, Tp = 11.7 s, h = 15 m, U= 1.5 m/s.5 Fh,max = 537 kn Fh,min = -183 kn Mmax = 8535 knm M Mmin = knm --eta*1-1 ========== ' X :::::: 5. C1l <J) ><: C1l :::::: <( -5 Sampling No. -C1l Fore [kn] Fore [kn) X 14 lj._ ' o x. Prob. [%) x. Prob. [%) Vi' 8.s ]!;- 6 'iii 4 "' ' ti a. Cl) ) --F11 --JONSWAP 3 F11 --Rayleigh o =L o 1 Frequeny[H] x. Prob. [%)

24 Wave Fores on Windturbine Foundations for the London Array F1 With a onrete one Hmo =.5 m, Tp = 6.5 s, h = 9 m Fh,max = 3339 kn F h,min = kn Mmax = knm Mmin = knm X M --eta*1-4 ========== ' :g. Cl) en Cil : X L Sampling No , F MWL (l... Cl) -5-1L _ : u.. - Fore [kn] L- 1 o 1 Fore [kn] X : o x. Prob. [%] x. Pro b. [%] 15 r r============= I == :SWAP I N 1.. en " 5 t5 D.. C/) Frequeny [H] F Rayleigh o 1 o x. Prob. [%] 3

25 Wave Fores on Windturbine Foundations for the London Array F13 With a onrete one Hmo = 5.6 m, Tp = 9.1 s, h = 9 m Fh,max = 5381 kn Fh,min = -551 kn Mmax = knm Mmin = knm X 1 4 1, , 5 --M - - eta*1-5 ==========L_ ' X 1 4 =. 5 ::::::..Cl <ll (f) ;; >:: () g <x: Sampling No. F X Fore [kn] -5 1 o- 1 o x. Prob. [%] w 5 N.s 4 (f) ' t5.. (/) 3 1 ) - - F13 --JONSWAP Frequeny [H] F Rayleigh o 1 o- 1 x. Prob. [%] 4

26 Wave Fores on Windturbine Foundations for the London Array F14 With a onrete one Hmo= 6.84m, Tp= 11.7 s,h=9m Fh,max = 7867 kn Fh,min = kn Mmax = 1544 knm Mmin = knm X = 1 ' "' --eta*1-5 ========== ' Sampling No. ' =s g.5. ro QJ (J) eo -.5 QJ -1 L a.. ro Fore [kn] Fore [kn] =s QJ u.. 5, _...,,_...,...,..._;;;;;;;;;;;::=- -l ' =s :: QJ x. Prob. [%] x. Prob. [%] en N.s 1 "Ci) :: QJ " t> QJ a. (/) 5 --F14 --JONSWAP Frequeny [H] 4 r ======== F Rayleigh 1 x. Prob. [%] 5

27 Wave Fores on Windturbine Foundations for the London Array FlS With a onrete one Hmo =.71 m, Tp = 6.5 s, h = 1 m F h,max = 3615 kn Fh,min = kn Mmax = knm Mmin = -43 knm X 1 4, al...l.lll.llll.llll...llj.l.j.!l-, I - - F*1-1 I --M - - eta*1 - ========== Sampling No. X :. C1l (l) m ;; - (l) -4 : -4-4.s - a.. -"' C1l ::::: <( 1 F MWL : (l)... LJ... - Fore [kn] -4 1 o 1 o x. Prob. [%] (l) : 4 - X 1 4 Fore [kn] -4 1 o x. Prob. [% ] r;; 15 N.s m 1 (l) -o tl 5 (l).. (/) --F15 --JONSWAP Frequeny [H] <n :s 6 4 F Rayle igh -..._... 1 o 1 o x. Prob. [%] 6

28 Wave Fores on Windturbine Foundations for the London Array F16 With a onrete one Hmo = 5.17 m, Tp = 9.1 s, h = 1 m Fh,max = 531 kn Fh,min = kn Mmax = 6476 knm Mmin = knm X 1 4 4, M --eta*1-4 ========== Sampling No. ' X ro <l> (/) - <l> : Fore [kn] 5.. ->:: <( -5 1r----.r====== 4 6 Fo re [kn] <l> l..l o 1 o ' - <l> : x. Prob. [%] x. Prob. [% ] V> N.s q (/) <l> ".._ ro t5 <l>.. C/) j\_ - - F16 --JONSWAP 3 F16 --Rayle igh Frequeny [H] x. Pro b. [%] 7

29 Wave Fores on Windturbine Foundations for the London Array F17 With a onrete one Hmo=8.15m,Tp=11.7s,h = lm F h,max = 84 kn Fh,min = kn Mmax = knm Mmin = knm X F*1 --M --eta*1-1 ========== Sa mpling No. ' g 5.. ro - Cl) -.5 ::: ======.: 5 fj <( Fore [kn] Fore [kn ] _...,... LL.. ' 5 ::: x. Prob. [%] x. Prob. [%] 15o r r ============! == :SW 1 -o 5 a. (/) o ) Frequeny [H] 3 x. Prob. [% ] F Rayleig h 8

30 Wave Fores on Windturbine Foundations for the London Array F18 With a onrete one Hmo=.74m,Tp=6.5s,h = 15m F h,max = 319 kn Fh,min = -373 kn Mmax = knm Mmin = -366 knm X 1 4 4, M eta*1-4 ==========L_ C1J CfJ -C1J - X L L Fore [kn] Sa mpling No. 1, r-r======= F MWL :5.. : <( -5-1 L Fore [kn] - = L--- 1 o x. Prob. [%] -4L_ x. Prob. [%] 15 r =========== --F18.s "'. 'Cii 1 " 5 u a. (/') --JONSWAP 6r---========== F Rayleigh Frequeny [H] x. Prob. [%] 9

31 Wave Fores on Windturbine Foundations for the London Array F19 With a onrete one Hmo=4.86m,Tp=9.3s,h=15m Fh,max = 4963 kn Fh,min = kn Mmax = knm Mmin = knm X 1 4 ::::s g.d ro (J) -ro :::: Fore [kn] a...>.::.l3 X M - - eta*1-4 ========== Sampling No. F Fore [kn] 5 ::::s._ ll o x. Prob. [%] -5 1 o x. Pro b. [% ] Ci) N.s '(ii Cl) ' ti. (j) j\ --F19 --JONSWAP V> 4 3 F19 --Rayle igh Frequeny [H] o - 1- x. Prob. [%] 3

32 Wave Fores on Windturbine Foundations for the London Array F With a onrete one Hmo = 8.4 m, Tp = 11.3 s, h = 15 m Fh,max = 965 kn Fh,min = -698 kn Mmax = knm Mmin = knm X F*1 --M --eta*1-5 ==========L Sampling No. :.5. Cll QJ - Cf) -.5 :: : 5 :: a.. <t: Fore [kn] Fore -.5 X , _....., ' 5 -:: QJ x. Prob. [%) x. Prob. [%] 4, ========== F Rayle ig h Frequeny [H] x. Prob. [%] 31

33 Wave Fores on Windturbine Foundations for the London Array F1 With a onrete one Hmo = 3.51 m, Tp = 6.5 s, h = 9 m, U = 1.5 m/s Fh,max = 4991 kn F h,min = -444 kn M max = 6153 knm Mmin = knm X F* M --eta*1-4 ===========L ' e.... (/) - -: ::: Fore [kn] Sampling No. -1 ' " -5 5 Fore [kn] X e.. u_ '--- 1 o x. Prob. [%] ' e.. 5 ::: - 5 '--- 1 o x. Prob. [% ] 5 r r============= --F 1 "' 15 -o 1 t5.. (/) --JONSWAP Frequeny [H] 4 F Rayleigh ' o x. Prob. [%] 3

34 Wave Fores on Windturbine Foundations for the London Array F With a onrete one H mo = 8.19 m, Tp = 11.3 s, h = 15 m, U = 1.5 rn!s F h,max = 9894 kn F h,min = kn M max = knm M min = knm X M --eta*1-5 ==========L ' X 1 5 =..5.D ro <I> (/) -ro -.5 <I> :: Fore [kn] X 1 4 Sampling No. 1 r ======.: 5 a.. <X: Fore [kn] X <I>... u.. ' =. - <I> o, x. Prob. [%] 1 x. Prob. [%] 7ii' N.s 15 (J) 1 -o t5 5 <I> a. (f) --F --JONSWAP } Frequeny [H] 3 " F --Rayleigh 1 x. Pro b. [%] 33

35 Wave Fores on Windturbine Foundations for the London Array F3 With the shaft of the one Hmo =.69 m, Tp = 6.5 s, h = 9 m Fh,max = 384 kn Fh,min = -48 kn Mmax = 19 knm M min = knm X , M --eta*1-1 ========== '!S g. < (!) CfJ -< -:: Cl)!S (!) u Fore [kn]...? x. Prob. [%] Sampli ng No. 1, , ,.: 5 :: a.. ::;: -5 F3 I MWL. -1 L..!:===== =:::!..J !S -:: (!) Fore [kn ] ::; x. Pro b. [%] Cii' N.s CfJ :: (!) -o 1:3 Cl). (/') 15 1 I == :SWAP I 5 ) Frequeny [H] ";- 4 V) ::s 6 F3 - - Rayle igh 1 o x. Prob. [% ] 34

36 Wave Fores on Windturbine Foundations for the London Array F4 With the shaft of the one Hmo= 7.85m,Tp=11.3s, h = 15m Fh,max = 574 k.l\i Fh,min = -315 kn M max = knm Mmin = -85 knm X , ' :g.5..a Cll <1) (/) : -.5 <1) Fore [kn] 5...::.:. g Sam pling No. 1, ,... <t: -5 F MWL -1 L _..._====::!J Fore [kn] X 1 4 1, <1) u o x. Prob. [% ] ' 5 <1) x. Prob. [%] Ui" 15 r r========jl --F4.s N 1 (/) <1) " --JONSWAP 5 I J F Rayleigh Frequeny[H] x. Prob. [%] 35

37 Wave Fores on Windturbine Foundations for the London Array Appendix - Models All measures in meters - prototype values. Monopile:. V

38 Wave Fores on Windturbine Foundations for the London Array Conrete one: % %