HLRB Project pr83la

Fully-resolved, finite-size particles in statistically stationary, homogeneous turbulence

Institut für Hydromechanik

Fully-resolved, finite-size particles in statistically stationary, homogeneous turbulence

Institut für Hydromechanik

Institut für Hydromechanik

Prof. Markus Uhlmann

Kaiserstrasse 12

76131 Karlsruhe

The present project aims to provide a complete description of the dynamical interaction between a sustained turbulent flow and a large number of suspended, heavy and rigid particles in an unbounded domain. This idealized configuration still contains the fundamental mechanisms governing such diverse processes as the collision-induced growth of rain drops in clouds, segregation of particles in chemical engineering devices and sediment dynamics in water bodies. Our first goal is to generate high-fidelity flow (and particle motion) data by means of direct numerical simulation of the Navier-Stokes equations using a finite-difference technique in conjunction with an immersed boundary method. The data-set will allow us to elucidate the physics of turbulence-particle interactions and serve as a benchmark for reduced-complexity particulate flow models. The novelty of the configuration considered in the present study is two-fold. First, the system size and the resolution is unprecedented and would not be possible without considerable HPC resources on a system such as SuperMUC. Secondly, no previous numerical study has targeted homogeneous turbulence interacting with a large number of heavy particles which are settling due to gravity. This case is especially challenging, since a wake flow forms downstream of each sedimenting particle, leading to such intricate phenomena as wake-induced large-scale agglomerations. These clusters, in turn, affect the average settling velocity, the fluid flow field, etc. The open questions upon which we attempt to shed light with the aid of the data to be generated in the present project include the following: How does background turbulence affect the formation of wake-induced particle clusters? How are the competing effects of turbulence and wake-attraction reflected in macroscopic quantities such as the average particle settling rate? Do finite-size settling particles exhibit preferential accumulation with respect to coherent vortical structures of the turbulent background flow?

Impressum, Conny Wendler