Wave field generated by finite-span hydrofoils operating beneath a free surface

Yavuz Hakan Ozdemir, Taner Cosgun*, Baris Barlas

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

The present paper focuses on the numerical investigation of the flow around the fully submerged 2D and 3D hydrofoils operating close to a free surface. Iterative boundary element method is implemented to predict the flow field. This study aims to investigate the aspect ratio effect on the free surface interactions and hydrodynamic performance of the hydrofoils under a free surface by using potential flow theory. Three different submergence depths and aspect ratios are studied in the wide range of Froude Numbers. In 3D cases, spanwise width of the numerical wave tank model is selected both equal and wider to the foil span, to observe the sidewall effects. Wave field seems to be two dimensional at low Froude numbers. On the other hand, signs of three dimensionalities are observed on the free surface structure for higher Fn, even the predicted wave elevations are very close to 2D calculations in the midsection. Increment in the Fn give a rise to the amplitude of the generated waves first, however a further increase in Fn has a lowering effect with the beginning of waves spill in the spanwise direction in the form of Kelvin waves. Free surface proximity and resultant wave field are also seeming to be linked with the lift force on the hydrofoil. As aspect ratio of the foil increase, 3D lift values are getting closer to those of 2D calculations. However, it is seen that, 3D BEM predictions of a hydrofoil under free surface effect cannot be considered twodimensional even the aspect ratio is equal to 8.

Original languageEnglish
Pages (from-to)145-167
Number of pages23
JournalBrodogradnja
Volume72
Issue number1
DOIs
Publication statusPublished - 2021

Bibliographical note

Publisher Copyright:
© 2021, Brodarski Institute. All rights reserved.

Funding

This work was supported by Canakkale Onsekiz Mart University Research Coordination Unit, Project number: FBA-2019-2984

FundersFunder number
Çanakkale Onsekiz Mart ÜniversitesiFBA-2019-2984

    Keywords

    • Aspect ratio
    • Computational fluid dynamics
    • Free surface
    • Iterative boundary element method
    • Potential flow
    • Submerged hydrofoil

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