Tsunami Bore Impingement onto a Vertical Column

Abstract

In a laboratory wave tank, bores were generated by dam-break: by lifting a gate that initially separated quiescent shallow water from a volume of impounded water. The study was motivated by the problem of tsunami-structure interaction and sought to further the understanding of interactions between the bore-like flow of a broken tsunami wave and structures of different cross sections. Experiments were designed to observe the structure’s effect on the bore as well as the bore’s effect on the structure. This comprehensive study used highly repeatable experiments to measure water-surface variations, velocity flow fields, and forces exerted by bores on vertically erected columns. The temporal and spatial variations of the water-surface elevations were quantified with a Laser-Induced Fluorescence (LIF) technique; velocity flow fields were recorded with a combination of Laser Doppler Velocimeter (LDV) and Digital Particle Image Velocimetry (DPIV); forces on the columns were measured with a miniature load-cell transducer. The laboratory data obtained in the study are available for validating numerical models that predict forces on structures in unsteady flows.

Example of wave impact on a residential house

“…On coastal areas around the Indian Ocean and at the mountains close to dam sights, most of the buildings do not exceed three floors, resulting into low structures characterised by a rectangular shape. Some previous relevant studies on wave impact against free standing structures were conducted by Cross (1967), Ramsden (1996), Arnason et al (2009) and Nuori et al (2010); it is also worth mentioning the Japanese contribution of Asakura et al (2000) and Okada et al (2005). Investigations on the behaviour of residential houses subject to wave impact were carried out by Thusyanthan and Madabhushi (2008), who tested a "tsunami resistant house" designed by Harvard design school in collaboration with MIT and compared it with a typical house in Sri Lanka.…”

A multivariate generalized linear tsunami fragility model for Kesennuma City based on maximum flow depths, velocities and debris impact, with evaluation of predictive accuracy

“…In order to provide better tools to decision makers, engineers and the risk assessment community in exposed countries, it is necessary to further our understanding of structural failure mechanisms under tsunami loads and to improve the predictive ability of current models to estimate future potential tsunami damage. While from a deterministic standpoint some noticeable advancements are being made on the identification of wave inundation processes and actions of tsunami forces, from both large-scale hydraulic experiments (Arikawa 2009;Arnasson et al 2009;Charvet et al 2013a;Lloyd 2014), field surveys (Chock et al 2013;EEFIT 2013), as well as simulation with particle-fluid mixture flows (Pudasaini 2014), from a probabilistic perspective the likelihood of future tsunami-induced building damage, or fragility estimation, still requires considerable improvements in order to reduce the uncertainty associated with the predictions (Suppasri et al 2013a;Charvet et al 2014a, b). Fragility estimations are obtained through the derivation of fragility functions, which are empirical stochastic functions giving the probability that a building will reach or exceed a given level of damage for a measure of tsunami intensity (IM).…”

Mean Normalized Force Computation for Different Types of Obstacles due to Dam Break Using Statistical Techniques

“…In this study, experimental results of Arnason et al [19,20] are used for predicting mean normalized forces on obstacles due to dam-break. The experiments are performed in a wave channel, which is 16.6 m long, 0.6 m wide and 0.45 m deep, with glass sidewalls.…”

“…In this study, the most recent test results by Arnason et al [19,20] are followed to develop an efficient and practical formula for predicting mean normalized forces exerting on different types of obstacles, in terms of engineering design perspective. For this purpose, (1) five statistical procedures are performed to investigate both the most parsimonious and most appropriate model that cannot violate the restrictive assumptions; (2) new variable that can take into account the shape of the obstacles exposed to dam break wave is suggested; (3) a new and practical formula for predicting the mean normalized force is suggested for different types of obstacles, which is missing in the previous research.…”