Preferential rotation of chiral particles in turbulence is driven by orientation dependent handedness

We study the dynamics of chiral particles sedimenting in 3D homogeneous turbulence and how the dynamics depend on particle shape. We perform experimental measurements in a vertical water tunnel under influence of gravity and turbulence. In 3D turbulence that is approximately homogeneous and isotropic, we measure the translational and rotational dynamics of three-bladed propellers. We investigate key aspects of propeller dynamics, including position, velocity, rotation rate and the coupling between rotational and translational motion. The mean vertical component of the rotation rate of the chiral particles is nearly zero because of a cancellation between orientations with right and left handed translation-rotation coupling. However, when we condition the rotation rate on orientation, we find strong chiral coupling that depends on the orientation of the particle with respect to the relative velocity. We then compare the results with equivalent achiral particles.