Journal of Mountain Science

, Volume 14, Issue 4, pp 649–661

Wave attenuation mechanism of cross-plates applied in landslide-induced tsunami in river course

Article

Abstract

Since the impounding of the Three Gorges Reservoir, the channel of the Yangtze River has become a busy watercourse and the probability of landslide-induced tsunamis has increased. In the case of landslide-induced tsunamis in the Three Gorges Reservoir, even after shipping closures in advance, there are still facilities and objects in urgent need of protection within the risk zone of the watercourse, such as wharfs, marine fueling stations, berthed ships. The emergency protection against and decay of landslide-induced tsunamis in inland watercourses is a new challenge. In this study, 37 sets of wave decay experiments were conducted with the hydromechanics numerical method. The wave decay efficiencies of common simple structures including submerged horizontal plate, horizontal plate on the water surface, inclined thin plate and cross-plates in coastal areas were compared and analyzed. Cross-plates structure showed better wave decay capacity than other simple plates. The wave decay performance of cross-plates was related to five modes of energy dissipation and transformation, namely run-up/run-down, overtopping, reflecting, return flow and disturbed wave orbital path. The type of wave had little relation with the decay performance of cross-plates, but a strong correlation with cross-plates structure, especially the height of the vertical emerged plate. The best decay performance was observed when the ratio of wave amplitude to emerged vertical plate height was between 1 and 1.5, which can reduce up to about 80% of the incoming wave amplitude. Finally, the emergency way of cross-plates applied to the decay of landslide-induced tsunami in river course is discussed. This study provides a conceptual reference for related studies to practice the attenuation of landslide-induced tsunami in reservoirs.

Keywords

Landslide-induced tsunami Cross-plates Wave decay Energy dissipation Attenuation mechanism 

Notation

WP

Without the cross-plates

HP

Horizontal plate on the water surface

SHP

Submerged horizontal plate

ITP

Inclined thin plate

CP

Cross-plates

Ct

Transmission coefficient

H0

Maximum original wave amplitude without structure

Ht

Maximum wave amplitude with different structures

Ha

Wave amplitude

WV

Wave boundary

P

Zero-pressure boundary or free water surface boundary

W

Wall boundary

S

Symmetrical boundary

La

Original height of the above-water vertical plate

Lm

Original height of vertical plate in the water

Lf

Length of horizontal plate facing the incoming wave

Lr

Length of the horizontal plate facing away from the incoming wave

Hx

A critical height of above-water vertical plates

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Copyright information

© Science Press, Institute of Mountain Hazards and Environment, CAS and Springer-Verlag Berlin Heidelberg 2017

Authors and Affiliations

  1. 1.Key Laboratory of Disaster Prevention and Mitigation of Hubei ProvinceYichangChina
  2. 2.Wuhan Center of China Geological SurveyWuhanChina

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