Experimental Comparison of Wave Interaction with Porous Media

The objective of this work is to study how to minimise wave reflection in the wave channel of the Universidad del BioBio Wave Lab by means of different porous media. The experimental study was made defining six initial wave states, in which all experiments were carried out. Four situations were compared: first, without any wave absorber; second with a sponge wave absorber already present in the channel; third with a porous plate absorber in series; and finally with a triangular mesh absorber with sponges. Wave train-free surface elevation data were collected using three carefully spaced ultrasound sensors and used to calculate the reflection coefficient associated with each wave structure and parameter. The results revealed that the first scenario showed the highest reflection coefficient, while the second scenario showed the second highest reflection coefficient. On the other hand, the third situation presented the lowest reflection coefficient, and in the last situation, a slightly higher coefficient than the third case was obtained. These results highlight the efficiency of the two proposed absorber structures and their performance in reflection reduction. In conclusion, the porous plate absorber showed higher mitigation of the reflection, followed by the triangular mesh absorber and sponges. This study could contribute to future research conducted in the wave-generating channel, providing valuable insight for practical applications in the field of coastal research and engineering.