Nonlinear Resonant Interaction between a Surface Wave and Harmonic Interfacial Waves

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Sadeghi, Nayer | 2010

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Type of Document: M.Sc. Thesis
Language: Farsi
Document No: 40667 (09)
University: Sharif University of Technology
Department: Civil Engineering
Advisor(s): Jamali, Mirmosadegh
Abstract:
The three dimensional resonant interaction between a surface wave and harmonic interfacial waves in a horizontally infinite two-layer fluid was investigated theoretically and experimentally. Initially, both layers assumed to be inviscid, but after obtaining the final equations of the interfacial wave's amplitude, with perturbation, the viscous damping effect, was incorporated in to the interaction equations. It is shown that, surface wave can trigger four opposite- traveling interfacial waves whose amplitudes grow with time. But because of viscosity damping effect, these amplitudes will become constant and won't change with time. The frequencies of the interfacial waves are approximately equal to the frequency of the surface wave. Harmonic and subharmonic theories were compared. It is shown that, only for surface wave with long period, harmonic interfacial waves will appear, otherwise subharmonic waves will generate. Experiments were carried out to test the theoretical results. The experiments confirm the theoretical predictions. As shown by the theory, the diffuse layer lead to bigger grow rate and smaller ultimate amplitude
Keywords:
Resonant Interaction ; Harmonics ; Resonance ; Perturbation Method

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