Numerical investigation of transient harbor oscillations induced by N-waves

Abstract

Tsunamis are traveling waves characterized by large amplitudes and long wavelengths close to the coastline. Often, the first couple of leading waves are either leading-elevation N-waves (LEN waves) or leading-depression N-waves (LDN waves). These waves are usually devastating, causing serious damage to coastal infrastructures or even human casualties. Among various natural disasters related to tsunamis, harbor oscillations are one of the most frequent disasters around the world, which can cause excessive movements of moored ships and rupture mooring lines inside the harbor. In this article, transient harbor oscillations induced by various incident N-waves are first investigated. The transient oscillations are simulated by a fully nonlinear Boussinesq model, FUNWAVE-TVD. The incident N-waves include the TS-type and MS-type isosceles LEN and LDN waves. The TS-and MS-type N-waves correspond to the waveform expressions proposed by Tadepalli and Synolakis [1] and Madsen and Schä ffer [2], respectively. This paper focuses on the effects of the incident wave amplitude and its type on the relative wave energy distribution inside the harbor. The maximum runup and rundown of various incident waves are also discussed. For comparison, the transient oscillations excited by solitary waves are also considered. The harbor 

Numerical study on transient harbor oscillations induced by successive solitary waves

“…This phenomenon is quite different from the corresponding finding in Gao et al (2017a) about the transient harbor oscillations excited by the N-waves. Gao et al (2017a) found that for various types of incident N-waves, the resonant mode that possesses the highest wave energy shifts gradually from a lower mode to the higher mode with the increase of the incident wave amplitude. is defined as…”

“…To verify the applicability of FUNWAVE-TVD to the simulation of transient harbor oscillations induced by tsunamis, Gao et al (2017a) used the numerical model to reproduce the laboratorial and numerical experiments of Dong et al (2010). Gao et al (2017a) compared the maximum oscillation inside the harbor predicted by FUNWAVE-TVD with the experimental and numerical data of Dong et al (2010).…”

“…Harbor oscillations are originated by the trapping and amplification of wave energy at the eigenfrequencies of coastal semi-enclosed water bodies, such as bays and harbors. They may be induced by short wave groups, infragravity waves, tsunamis, wind and pressure fluctuations and shear flow traveling into bays or harbors (Bellotti and Franco, 2011;Bowers, 1977;Chen et al, 2004; De Jong and Battjes, 2004;Dong et al, 2013;Dong et al, 2010;Fabrikant, 1995;Gao et al, 2016a;Gao et al, 2017a;Gao et al, 2017b;López and Iglesias, 2013;López et al, 2012;López et al, 2015;Maa et al, 2011;Pattiaratchi and Wijeratne, 2009). Harbor oscillations can have direct influence on the management of ports, shipping and coastal utilization.…”

“…Meanwhile, to compare similarities and differences between oscillations induced by successive solitary waves and those by the single solitary wave, the transient resonance excited by the latter is also simulated, which has been investigated by Gao et al (2016b) and Gao et al (2016c) and is only taken as a control group in this paper. Identical to Gao et al (2017a), all numerical experiments in this article are performed using the fully nonlinear Boussinesq wave model, FUNWAVE-TVD. For simplification, the harbor is assumed to be long and narrow and has a flat bottom; the free-surface movement inside the harbor then essentially becomes one-dimensional.…”

Numerical investigation of infragravity wave amplifications during harbor oscillations influenced by variable offshore topography

“…Better understanding of wave trapping and amplification in bays and harbors is of vital importance to many practical applications. Several external forcings such as tsunamis originating from distance earthquake, longshore-propagating edge waves, wind and pressure fluctuations, shear flow and impact waves induced by landslides or the failure of structures near the harbor have been shown to drive these oscillations (Chen et al, 2004;De Jong and Battjes, 2004;Dong et al, 2010a;Fabrikant, 1995;Gao et al, 2017a;Gao et al, 2015Gao et al, , 2016cMaa et al, 2011;Pattiaratchi and Wijeratne, 2009). However, the primary source of infragravity (IG) waves energy is the nonlinear wave-wave interaction of short wave groups propagating in shallow waters (Bowers, 1977;Mei and Agnon, 1989;Wu and Liu, 1990).…”