RIASSUNTO
ABSTRACT
Artificial reefs are common human-made structures placed purposefully on the seabed for fishery enhancement and coastal protection. The local flow patterns could be further created and designed by perforated artificial reefs to become more inhabitable for different fish species, which attracts more attentions from researchers. Thus, based on the Particle Image Velocimetry (PIV) technology, the primary focus of this research is to investigate the flow field of perforated artificial reefs arranged longitudinally with two perforated blocks, and to compare with the flow field of the single reef with the same structure. The results show that, the turbulent flow regime inside and outside the twin-block perforated reef consists of vortices interaction patterns and the main flow becomes weaker along the current direction. Several vortices with different scales are formed inside and behind the reef, and the vortex structure displays certain symmetry in the transverse direction because of symmetrical reef structure. Comparing with the flow field of a single perforated reef, the increase in reef number has little effect on the vertically vortical structure within the reef compartments. However, the influence range and sheltering effect induced by the twin-block reef becomes greater than that in the single reef. This research reveals the geometrical relationship between perforated reef structure and internal flow pattern, and provides a scientific guidance for optimizing the structure and deployment of perforated artificial reefs.
INTRODUCTION
Artificial reefs are common human-made structures, which are deployed on the seabed to emulate some features of natural reefs, such as protecting, concentrating and enhancing populations of fish. Since the early of 19th century, when artificial reefs began to be used for proliferation of marine fishery and restoration of ecological environment, a great deal of researches of artificial reefs have been focused on the biological, chemical and marine environment aspects (Simon et al., 2011; Chen et al., 2019; Gates et al., 2019; Wu et al., 2019).