Particles and fibres in homogeneous isotropic turbulence

We investigate how spheres and fibers of finite size can modify a homogeneous, isotropic turbulent flow. A decrease in the micro-scale Reynolds number characterizes the bulk effect that is produced by both spheres and fibers. A spectrum examination of the flows reveals how fundamentally different the multiscale effects of the two suspensions are. For spheres, the flow is altered at scales comparable to its diameter, while at smaller scales there is little change in the flow, and the canonical turbulent energy cascade is recovered. For fibers, modulation spans a much greater range of length-scales, from its length to its thickness, and a new turbulent kinetic energy scaling is found.