Finite-size particles interacting with non-homogeneous turbulence

• Applicant: Professor Dr. Markus Uhlmann
• Subject Area: Fluid Mechanics
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 529941008

Dispersed two-phase flows occur in many industrial applications and natural phenomena, ranging from plastic transported in oceans, to sprays in engines. Plastic transport prediction or efficiency and environmental impact of propulsion depend on the ability to predict and control flows containing heavy particles which are submitted to the combined action of gravity and turbulence. The turbulent transport of inertial particles smaller than the smallest flow length-scale has been widely investigated, but the case of finite-size particles with density moderately larger than the fluid and in the presence of gravity has only been explored to a much lesser extent, so that a significant number of open questions remain: how does the carrier flow turbulence affect the motion of moderately heavy, finite-size particles? How do they sample the turbulent fluid velocity field along their trajectory, and what is their settling velocity? Do they form clusters, and how do they affect the carrier turbulence when their concentration increases? These knowledge gaps are currently blocking further progress towards predictive models for engineering purposes. The present project proposes to study these effects with cutting-edge experimental techniques and fully resolved direct numerical simulation to combine the advantages of the two approaches: covering a wide range of parameters with partial information in experiments with a smaller number of fully coupled numerical simulations providing full information. This will allow to investigate dynamics from the system size down to the very small scales in the near-field around the particles with clear interpretation of the energy balance. This approach will lead to data covering for the first time a wide parameter space (particle size, density ratio, Galileo and Reynolds numbers, solid volume fraction). The results can be expected to advance our knowledge and the modelling of the dynamics of particle-turbulence interaction significantly.

• DFG Programme: Research Grants
• International Connection: France
• Cooperation Partner: Dr. Romain Volk