Experiments on the Bragg reflection of waves by different types of artificial bars

Experiments were performed to demonstrate Bragg reflection between linear gravity wave and artificial bars. Higher-harmonic and sub-harmonic Bragg-reflections have been observed in a wave flume. Three different artificial bars with rectangular, triangle and sinusoidal shapes were placed discretely on the seabed to make a measurement of Bragg reflection. A series of experimental conditions including the number of bars, the periodic bar spacing, the footprint of the bar, the bar height and various wave conditions were tested. Key parameters affecting Bragg reflection were discussed. The experimental data are compared with the predictions of a bar theory and a numerical model.