Experimental analysis of debris motion due the obstruction from fixed obstacles in tsunami-like flow conditions

Abstract

Experimental research was conducted focusing on debris motion over a horizontal apron featuring vertical obstacles in the path of the debris propagation. The apron was designed as a typical representation of a harbor threatened by an inundating tsunami. The experimental setup idealized often complex harbor settings. The debris was a scaled-down 20-foot shipping container modelled at a 1 in 40 Froude length scale. Offand onshore regions were separated by a vertical quay wall which allowed the incoming elongated solitary wave used to represent the first part of a tsunami to steepen, break and propagate over the initially dry surface as a tsunami-like bore. In the path of propagation, a varying number of debris were entrained within the inundating bore over the horizontal apron. The entrained debris interacted with regularly spaced vertical obstacles representing infrastructure and houses within the propagation path. Varying debris and obstacle arrangements were tested to evaluate the effects the obstacles would have on the debris' maximum longitudinal displacement and the spreading angle. The main conclusion is that the spreading angle of the debris is not as significantly altered by the presence of obstacles on the harbor apron whereas the maximum longitudinal displacement of the debris was significantly affected.