Flow Turbulence Characteristics and Mass Transport in the Near-Wake Region of an Aquaculture Cage Net Panel

Cage-based aquaculture has been growing rapidly in recent years. In some locations, cage-based resulted the clustering of large quantities cages fish farms located inland lakes or reservoirs and coastal embayments fjords, significantly affecting flow mass transport surrounding waters. Existing studies have focused primarily on macro-scale blockage effects cages, complex wake associated near-field presence remain largely unclear. As a first step toward resolving this knowledge gap, study employed combined Particle Image Velocimetry Planar Laser Induced Fluorescence (PIV-PLIF) imaging technique to measure turbulence characteristics near steady current through an cage net panel parametric flume experiments. near-wake region, defined as ~3M (mesh size) downstream net, was observed be highly inhomogeneous anisotropic nature. Further downstream, turbulent intensity followed power-law decay after production albeit with exponent much smaller than reported values for analogous grid-generated turbulence. Overall, slightly enhanced lateral spreading scalar plume, but distribution concentration, concentration fluctuation transverse flux exhibited self-similarity from region where still strongly inhomogeneous. The apparent diffusivity estimated gross plume parameters found reasonable agreement Taylor calculated product velocity integral length scale, even when development transitioning turbulent-convective turbulent-diffusive regime. findings provide references which important implications assessment environmental impacts carrying capacity aquaculture.