Higher harmonics induced by waves propagating over a submerged obstacle in the presence of uniform current

De zhi Ning, Hong xing Lin, Bin Teng, Qing ping Zou

Research output: Contribution to journalArticle

Abstract

To investigate higher harmonics induced by a submerged obstacle in the presence of uniform current, a 2D fully nonlinear numerical wave flume (NWF) is developed by use of a time-domain higher-order boundary element method (HOBEM) based on potential flow theory. A four-point method is developed to decompose higher bound and free harmonic waves propagating upstream and downstream around the obstacle. The model predictions are in good agreement with the experimental data for free harmonics induced by a submerged horizontal cylinder in the absence of currents. This serves as a benchmark to reveal the current effects on higher harmonic waves. The peak value of non-dimensional second free harmonic amplitude is shifted upstream for the opposing current relative to that for zero current with the variation of current-free incident wave amplitude, and it is vice versa for the following current. The second-order analysis shows a resonant behavior which is related to the ratio of the cylinder diameter to the second bound mode wavelength over the cylinder. The second-order resonant position slightly downshifted for the opposing current and upshifted for the following current.

Original languageEnglish
Pages (from-to)725-738
Number of pages14
JournalChina Ocean Engineering
Volume28
Issue number6
DOIs
Publication statusPublished - Dec 2014

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Potential flow
Boundary element method
potential flow
boundary element method
Wavelength
wavelength
prediction
analysis
method
effect

Keywords

  • free mode
  • higher harmonics
  • HOBEM
  • wave-current interaction

ASJC Scopus subject areas

  • Oceanography
  • Renewable Energy, Sustainability and the Environment
  • Ocean Engineering
  • Mechanical Engineering

Cite this

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title = "Higher harmonics induced by waves propagating over a submerged obstacle in the presence of uniform current",
abstract = "To investigate higher harmonics induced by a submerged obstacle in the presence of uniform current, a 2D fully nonlinear numerical wave flume (NWF) is developed by use of a time-domain higher-order boundary element method (HOBEM) based on potential flow theory. A four-point method is developed to decompose higher bound and free harmonic waves propagating upstream and downstream around the obstacle. The model predictions are in good agreement with the experimental data for free harmonics induced by a submerged horizontal cylinder in the absence of currents. This serves as a benchmark to reveal the current effects on higher harmonic waves. The peak value of non-dimensional second free harmonic amplitude is shifted upstream for the opposing current relative to that for zero current with the variation of current-free incident wave amplitude, and it is vice versa for the following current. The second-order analysis shows a resonant behavior which is related to the ratio of the cylinder diameter to the second bound mode wavelength over the cylinder. The second-order resonant position slightly downshifted for the opposing current and upshifted for the following current.",
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Higher harmonics induced by waves propagating over a submerged obstacle in the presence of uniform current. / Ning, De zhi; Lin, Hong xing; Teng, Bin; Zou, Qing ping.

In: China Ocean Engineering, Vol. 28, No. 6, 12.2014, p. 725-738.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Higher harmonics induced by waves propagating over a submerged obstacle in the presence of uniform current

AU - Ning, De zhi

AU - Lin, Hong xing

AU - Teng, Bin

AU - Zou, Qing ping

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