Author

# Chinpu Zhou

Bio: Chinpu Zhou is an academic researcher from Cornell University. The author has contributed to research in topics: Cylinder & Diffraction. The author has an hindex of 1, co-authored 1 publications receiving 13 citations.

Topics: Cylinder, Diffraction, Wave propagation, Envelope (waves)

##### Papers

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TL;DR: In this article, the diffraction of a nonlinear nearly periodic wavetrain by a vertical circular cylinder is investigated using the multiple-scale perturbation method, where the envelope of the incident wavetrain is assumed to modulate slowly in the direction of wave propagation.

Abstract: Using the multiple-scale perturbation method, the diffraction of a nonlinear nearly periodic wavetrain by a vertical circular cylinder is investigated. The envelope of the incident wavetrain is assumed to modulate slowly in the direction of wave propagation. The relationship between the envelopes of incident and scattered waves is derived. It is shown that second-order scattered set-down waves propagate only at the long-wave velocity (gh)½. The formula for low-frequency wave forces acting on the cylinder is presented. The low-frequency wave forces, which are second-order quantities, are caused by set-down waves beneath the wavetrain and the results of the self-interactions of the leading-order first harmonic wave components. Numerical solutions are presented for the case where the wave envelope varies sinusoidally.

13 citations

##### Cited by

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TL;DR: In this article, an asymptotic theory is presented for a partially enclosed harbor attacked by short waves through the entrance, such free long waves can further resonate the natural modes of the harbour basin.

Abstract: Progressive short waves with a narrow frequency band are known to be accompanied by long set-down waves travelling with the groups. In finite depth, scattering of short waves by a large structure or a varying coastline can radiate free long waves which propagate faster than the incident set-down. In a partially enclosed harbour attacked by short waves through the entrance, such free long waves can further resonate the natural modes of the harbour basin. In this paper an asymptotic theory is presented for a harbour whose horizontal dimensions are much greater than the entrance width, which is in turn much wider than the short wavelength.

67 citations

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TL;DR: In this article, the authors obtained analytical solutions for the second-order low-frequency oscillations inside a rectangular harbour excited by incident wave groups by using the multiple-scales perturbation method.

Abstract: By using the multiple-scales perturbation method, analytical solutions are obtained for the second-order low-frequency oscillations inside a rectangular harbour excited by incident wave groups. The water depth is a constant. The width of the harbour entrance is of the same order of magnitude as the wavelength of incident carrier (short) waves, but small in comparison with the wavelength of the wave envelope. Because of the modulations in the wave envelope, a second-order long wave is locked in with the wave envelope and propagates with the speed of the group velocity. Outside the harbour, locked long waves also exist in the reflected wave groups, but not in the radiated wave groups. Inside the harbour, the analytical expressions for the locked long waves are obtained. Owing to the discontinuity of the locked long waves across the harbour mouth, second-order free long waves are generated. The free long waves propagate with a speed of (gh)½ inside and outside the harbour. The free long waves inside the harbour may be resonated in a low-frequency range which is relevant to the harbour resonance.

66 citations

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TL;DR: In this paper, a fully submerged horizontal plate has been suggested as a breakwater, and the method of eigenfunction expansion is used to solve for the reflection and transmission of the short waves.

Abstract: A fully submerged horizontal plate has been suggested as a breakwater. With a proper design in the length, thickness, and submerged depth of the plate, most of the incoming short waves can indeed be reflected. The method of eigenfunction expansion is used to solve for the reflection and transmission of the short waves. The present results agreed with earlier experimental data and in the long-wave limit. If the incident wave is bichromatic, a second-order long wave train accompanies the wave groups. This long wave train is also scattered by the horizontal plate. It is shown there that the scattered long waves exist on both sides of the horizontal plate even when the short waves are completely reflected. The long waves may prove to be a bigger hazard than the short waves, because the wave period of the long wave (1–3 min) is closer to the natural frequency of coastal structures.

35 citations

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TL;DR: In this paper, a new mechanism that could be responsible for excitation of long-period oscillations in partially enclosed harbours is discussed, based on the interaction between a shear flow and the harbour-basin natural mode and does not suppose any external exciting forces caused by wind waves, tsunami, etc.

Abstract: A new mechanism that could be responsible for excitation of long-period oscillations in partially enclosed harbours is discussed. This mechanism is based on the interaction between a shear flow and the harbour-basin natural mode and does not suppose any external exciting forces caused by wind waves, tsunami, etc. The growth rate of harbour oscillations is found in terms of a plane-wave reflection coefficient integrated on the wavenumber spectrum of the oscillating outflow field near the harbour entrance. Analytical considerations for simple shear flows (vortex sheet and jet) show that the growth rate changes its sign depending on the ratio of oscillation frequency to flow speed.

34 citations

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TL;DR: In this paper, the eigenfunction expansions method is used to study the incidence of monochromatic waves in coastal areas and it is shown that maximum short wave reflection is associated with maximum long wave transmission.

25 citations