Probing fluid torque with a hydrodynamical trap: Rotation of chiral particles levitating in a turbulent jet

A vertical turbulent jet is used to trap chiral particles. The particles are maintained in levitation and a stationary rotation regime is observed. The model particles used are composed of a sphere and a helical tail. The rotating performance of the particles is investigated as a function of the length and the twisting of their tails. In addition, the flow field around a spherical particle trapped in the jet is characterized by a 3D-particle tracking velocimetry technique. This flow characterization is used to compute the near-field velocity around a captured particle and to predict the rotation reported for the different geometries tested.