Frequency response of multi-degree-of-freedom hybrid offshore systems integrating wind and hydrokinetic turbines

Demir A. K., Balas C. E.

Results in Engineering, cilt.27, sa.105631, ss.1-15, 2025 (ESCI)

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 27 Sayı: 105631
  • Basım Tarihi: 2025
  • Doi Numarası: 10.1016/j.rineng.2025.105631
  • Dergi Adı: Results in Engineering
  • Derginin Tarandığı İndeksler: Emerging Sources Citation Index (ESCI)
  • Sayfa Sayıları: ss.1-15
  • Gazi Üniversitesi Adresli: Evet

Özet

Recent technological advancements have made marine energy a significant focus within renewable energy.

Offshore wind turbines are usually installed on monopile foundations up to a certain depth. When these

monopiles also support hydrokinetic turbines, they form combined hybrid systems. Natural frequency analysis is

one of the most critical design criteria for these systems. Traditionally, offshore wind turbines have been

analyzed using single-degree-of-freedom (SDOF) models. However, incorporating hydrokinetic turbines increases

the system’s complexity, requiring a multi-degree-of-freedom (MDOF) approach. This study performs a natural

frequency analysis based on a two-degree-of-freedom model for such hybrid systems. Compared with a previous

study, the analytical solution shows a difference of only 2.35 %, indicating strong consistency with the literature.

Moreover, a 24.59 % decrease in the system’s natural frequency is observed compared to the wind-only

configuration, emphasizing the need for higher-order modeling in hybrid systems.