Can we design turbulence? Turbulence is everywhere and yet our fundamental understanding and capabilities to control it remain limited. It is a remarkable property of turbulence that, rather irrespectively of the large-scale forcing mechanism, it rapidly tends to restore a universal (homogeneous and isotropic) state at smaller scales. This tendency to universality severely hinders our capability to modulate turbulence by acting on few (large-scale) degrees of freedom. To address such questions a large research program has been set up to investigate the possibility to shape turbulence with particles. This program will enter an unexplored terrain and design non-universal turbulence employing 'smart' particles (either chiral, magnetic or with both properties) capable of applying appropriate small-scale forcing. The particles will be designed to interact with helicity and small-scale structures, thus touching turbulence at its own core. It will moreover shed light on the physics of complex-shaped particles dispersed in turbulent flows as occurring in nature, take e.g. pollen, plant seeds, fish, bacteria, algae, phytoplankton or sediments. Deeper understanding of these systems will open up the way to technological applications.Project description
In this project, the PhD candidate will investigate experimentally the role of magnetic particles in turbulence at low and high densities with the possibility to steer the turbulence via external (time-dependent) magnetic fields. An experimental setup for the generation of homogeneous isotropic turbulence (French washing machine) will be designed. It should satisfy certain constraints such as optical access for Particle Image Velocimetry (PIV) and 3D Particle Tracking Velocimetry (3D PTV) applications and facilities for the production of magnetic fields to control the dynamics of the particles. Measurement of magnetic particle aggregates as well as the statistics of turbulence will be made possible as function of
turbulence and magnetic field strength. Typical size of the magnetic beads will be similar to the dissipative scale of turbulence and aggregates can form strings as long as the integral scale. Strong interaction and exchange of data with parallel PhD projects on chiral particles in turbulence and numerical studies of such systems is anticipated.Location
This subproject will be carried out within the Fluids and Flows group at the Department of Applied Physics (https://www.tue.nl/en/research/research-groups/fluids-and-flows/
) of Eindhoven University of Technology. The PhD candidate will be supervised by prof. H.J.H. Clercx, prof. F. Toschi and dr. R.P.J. Kunnen. This project is part of a larger NWO-Groot program in collaboration with University of Twente that encompasses also international partners.