313 水生微生物の遭遇と乱流構造の関係(大気・水環境数値シミュレーション)

抄録

Turbulence plays an important role for predator-prey interactions in aquatic environments. In the present study, the flow structures promoting the pradator-prey encounter events in turbulence are explored by a numerical experiment. An instantaneous turbulent flow field is extracted from direct numerical solutions of the Navier-Stokes equations. Both the predators and prey are assumed to be passively carried with the frozen flow. It is also assumed that the predators have prey-detection distances R that are in the viscous subrange. The trajectory of each planktonic organism is computed in the Lagrangian frame so that the time and position of the pradator-prey encounters can be detected. The numerical experiment shows that the strain rate of the velocity filed is the primary factor in controlling the encounter events.