KAKEN — Research Projects | Wave-induced sound pressure from artificial fish reefs and applicability to sea environment improvem

Grant-in-Aid for Scientific Research (C)

MIZUTANI Norimi  Nagoya University, School of Engineering, Dept.of Civil Engineering, Associate Professor, 工学研究科, 助教授 (10209760)

¥2,100,000 (Direct Cost: ¥2,100,000)

Precise numerical calculation is performed to simulate a flow around two-dimensional structures which were emploved in the experiments carried out in 1996. The pressure vibration are also calculated and their time variations and amplitude spectra are analyzed. The vortices formed around the structure and their behaviors are confirmed to be very similar to those observed in the experiments. Although, the high frequency vibration in the pressure was not able to be reproduced well in the simulation, the amplitude spectrum was well simulated to be increased in a certain frequency domain. This agree with the experimental results in qualitative.
Laboratory experiments are also conducted in the three dimensional wave basin using cubic type fish reef models. In the experiments effects of number of fish reef and their arrangements on the sound pressure are investigated. Based on the experimental study, following results are obtaind.
1) The installing another fish reef beside the existing one enlarges the velocity between the reefs, however, it does not increase the sound pressure. Similar result is obtained in outer region of the array of the fish reefs.
2) The sound pressure in front of the outer corner of the fish reef is enlarged by installing another one. These results suggest that the combined effect of interactions between wave and a group of fish reefs and between flow and each fish reef plays important roles on the characteristics of local sound pressure. This indicates the detail investigations on the arrangement are necessary in installing the fish reefs.