challenges and solutions for modelling of tidal turbines

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Challenges and solutions for modelling of tidal turbinesAll Energy 2012Lloyd’s RegisterMarine Renewable Energy Research

Peter DaviesRenewable Energy Global Technology LeaderMay 2012


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Can horizontal axis wind turbine software be used for tidal turbines?• Reynolds number is in the same range for wind and tidal

turbines• W/T BEM software has been used for tidal turbines• Some of the problems

• Different velocity profiles• Wake expansion may be restricted• Cavitation may be an issue


NREL software – used in project See paper by Buhl – 2005 The NWTC Design-Codes Suite: An Overview


Validation 1 - using data from BAHAJ et al 2007. Power and thrust measurements of marine current turbines under various hydrodynamic flow conditions in a cavitation tunnel and a towing tank. Renewable Energy, 32(3), pp. 407-426


Validation 2 - using data from BAHAJ et al 2007. Power and thrust measurements of marine current turbines under various hydrodynamic flow conditions in a cavitation tunnel and a towing tank. Renewable Energy, 32(3), pp. 407-426


Reasons for discrepancies

• Cavitation• Wake expansion• 2D v 3D lift and drag coefficients


Other options 1 – Harp_Opt see paper by SALE, D., NWTC Design Codes (HARP_Opt by Danny C. Sale). http://wind.nrel.gov/designcodes/simulators/HARP_Opt/.

http://wind.nrel.gov/designcodes/simulators/HARP_Opt/




Other options 2 – MB Dyn & Aero Dyn

Not tested for tidal but as using in AeroDyn should be OK Open source Multi Body (rather than modal model) Status of control system model unclear See paper “Free/Open Source Multibody and Aerodynamic

Software for Aeroelastic Analysis of Wind Turbines” Fanzhong Meng / Pierangelo Masarati / Michel van Tooren


Issues to consider in modelling the tidal energy resource• Turbulence (horizontal and vertical)• Wave influence on velocity (horizontal and vertical)• Wave spectrum• Tidal variation• Length of simulation


Options for modelling resource tested by LR

Description Tidal variation

Turbulence Wave simple

Irregular Wave

Random walk spreadsheet

No Simple Yes

TurbSim + spreadsheet

No Complex Yes

Custom programme

Yes Complex Yes


Custom programme – developed by LR


ConclusionsQuestions Conclusions

Is BEM software for HAWT valid for horizontal axis tidal turbines ?

Yes, but with some caution due to physical differences in operating regime

Can open source software for horizontal axis tidal turbines be used for tidal turbines ?

Yes, using FAST / Aero_Dyn has been demonstrated for tidal turbines

Are results from open source software reliable ?

Yes, but cavitation may be an issue

Can tidal resource be modelled ? Yes, several options are available

Are simple tidal resource models reliable ?

Yes for initial design studies


ANY QUESTIONS ?

Thank you for listening

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Peter Davies Renewable Energy Global Technology Leader

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T +44 (0)1224 267771E [email protected] www.lr.org/renewables

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