access icon free Modelling of a flap-type wave energy converter farm in a mild-slope equation model for a wake effect assessment

It is expected that large farms of wave energy converters (WECs) will be installed and as part of the consenting process it will be necessary to quantify their impact on the local environment. The objective of this study is to assess the impact a WEC farm has on the incoming wave field through the use of a novel methodology. This methodology assesses the changes of the significant wave height surrounding a flap-type WEC farm with a special focus on the lee of the farm. A time-dependent mild-slope equation model is employed to solve the propagation of surface waves and their interaction with the devices. The model represents the devices as obstacle cells with attributed absorption coefficients tuned against near-fields obtained from a boundary element method (BEM) solver. The wake effect of the farm is determined by using a step-by-step approach starting first with an assessment of one device and progressively incrementing to a larger number of flaps. The effect of incident sea states, device separations and water depth changes on the wake effect of the farm is also investigated. This work shows the potential of a WEC farm to reduce significant wave heights on the leeside.

Inspec keywords: wakes; wave power plants; boundary-elements methods

Other keywords: BEM solver; surface waves propagation; mild-slope equation model; wake effect assessment; time-dependent mild-slope equation model; flap-type WEC farm; flap-type wave energy converter farm; boundary element method

Subjects: Finite element analysis; Wave power

References

    1. 1)
      • 6. Beels, C., Troch, P., De Visch, K., et al: ‘Application of the time-dependent mild-slope equations for the simulation of wake effects in the lee of a farm of Wave Dragon wave energy converters’, Renew. Energy, 2010, 35, (8), pp. 16441661.
    2. 2)
      • 15. Sarpkaya, T., Isaacson, M.: ‘Mechanics of wave forces on offshore structures’ (Van Nostrand Reinhold Co., 1981).
    3. 3)
      • 13. Lee, C., Kim, G., Suh, K.D.: ‘Extended mild-slope equation for random waves’, Coast. Eng., 2003, 48, (4), pp. 277287.
    4. 4)
      • 9. Troch, P., Stratigaki, V.: ‘Phase-resolving wave propagation array models’, in Foley, M. (Ed.): ‘Numerical modelling of wave energy converters: state-of-the-art techniques for single devices and arrays’ (Elsevier, 2016,) pp. 191216.
    5. 5)
      • 12. Lee, C., Suh, K.D.: ‘Internal generation of waves for time-dependent mild-slope equations’, Coast. Eng., 1998, 34, (1-2), pp. 3557.
    6. 6)
      • 8. Babarit, A., Delhommeau, G.: ‘Theoretical and numerical aspects of the open source BEM solver NEMOH’. Proc. 11th European Wave and Tidal Energy Conf., 2015, pp. 112.
    7. 7)
      • 1. Borgarino, B., Babarit, A., Ferrant, P.: ‘Impact of wave interactions effects on energy absorption in large arrays of wave energy converters’, Ocean Eng., 2012, 41, pp. 7988.
    8. 8)
      • 10. Troch, P.: ‘MILDwave – a numerical model for propagation and transformation of linear water waves’. Internal Report, Department of Civil Engineering, Ghent University, 1998.
    9. 9)
      • 11. Radder, A.C., Dingemans, M.W.: ‘Canonical equations gravity waves, weakly nonlinear gravity waves’, Wave Motion, 1985, 7, pp. 473485.
    10. 10)
      • 4. Astariz, S., Abanades, J., Perez-Collazo, C., et al: ‘Improving wind farm accessibility for operation & maintenance through a co-located wave farm: influence of layout and wave climate’, Energy Convers. Manag., 2015, 95, pp. 229241.
    11. 11)
      • 3. Smith, H.C.M., Pearce, C., Millar, D.L.: ‘Further analysis of change in nearshore wave climate due to an offshore wave farm: An enhanced case study for the wave hub site’, Renew. Energy, 2012, 40, (1), pp. 5164.
    12. 12)
      • 14. Zhao, H.t., Sun, Z.L., Hao, C.L., et al: ‘Numerical modelling on hydrodynamic performance of a bottom-hinged flap wave energy converter’, China Ocean Eng., 2013, 27, (1), pp. 7386.
    13. 13)
      • 7. Folley, M., Babarit, A., Child, B., et al: ‘A review of numerical modelling of wave energy converter arrays’. Proc. 31st Int. Conf. on Ocean, Offshore and Arctic Engineering, Rio de Janeiro, Brazil, July 2012, pp. 535545.
    14. 14)
      • 5. Beels, C., Troch, P., De Backer, G., et al: ‘Numerical implementation and sensitivity analysis of a wave energy converter in a time-dependent mild-slope equation model’, Coast. Eng., 2010, 57, (5), pp. 471492.
    15. 15)
      • 2. Mcnatt, J.C., Venugopal, V., Forehand, D.: ‘A novel method for deriving the diffraction transfer matrix and its application to multi-body interactions in water waves’, Ocean Eng., 2014, 94, pp. 173185.
http://iet.metastore.ingenta.com/content/journals/10.1049/iet-rpg.2016.0962
Loading

Related content

content/journals/10.1049/iet-rpg.2016.0962
pub_keyword,iet_inspecKeyword,pub_concept
6
6
Loading