A laboratory realization of the Burgers' vortex cartoon of turbulence‐plankton interactions

Abstract

AbstractA laboratory apparatus was constructed to physically realize the Burgers' vortex cartoon of turbulence‐plankton interactions. Fluid motion is induced by corotating two disks while simultaneously withdrawing fluid axially through hollow drive shafts. The technique creates a flow pattern that mimics a Burgers' vortex with size and strength consistent with turbulence vortices in the coastal and near‐surface zones. Specifically, the radius, circulation, and axial strain rate of the Burgers' vortex were specified to match typical dissipative vortices corresponding to two turbulence intensity levels (described by a mean turbulent dissipation rate of 0.009 cm2 s−3 and 0.096 cm2 s−3, respectively). Tomographic particle image velocimetry was used to quantify the flow field, calibrate the apparatus, verify that it produces the desired vortex characteristics, and provide a three‐dimensional velocity vector field to compare with zooplankton behavioral assays. The apparatus facilitates direct examination of the mechanistic aspects of plankton interaction with a turbulent‐like vortex, which is demonstrated via quantifying the swimming behavior of Acartia tonsa in and around the vortex flow structure.