EXPERIMENTAL STUDY ON RESONANCE IN A NARROW GAP DUE TO NEARBY RECTANGULAR CYLINDERS UNDER WAVES

A laboratory experiment was conducted for experimental confirmation of the appearance of resonant phenomena in a narrow gap due to nearby rectangular cylinders under waves. In the experiment, we used a 2-D wave flume and assumed an infinite array of caissons with a finite length and a narrow gap width. A theoretical analysis was then conducted for the case where an infinite solid wall with a uniform narrow gap is settled against the incident waves, as a first step toward estimating the theoretical resonant wave number corresponding to the experimental conditions. Consequently, resonant phenomena in the gap were found at kL≈π(k is the wave number and L is the gap length). The maximum wave height in the gap was more than nine times as large as the incident wave height. A theoretical non-dimensional resonant wave number was derived using an asymptotic matching method, and it was shown that the possible resonant wave number became kL=nπ(n=1, 2, ., .) as the gap width approached zero.