Rotational dynamics of bottom-heavy rods in turbulence from experiments and numerical simulations

Theoretical and Applied Mechanics Letters

Enrico Calzavarini¹  Cheng Wang²  Shuang Liu²  Chao Sun²  Linfeng Jiang² 

[1] Department of Engineering Mechanics, School of Aerospace Engineering, Tsinghua University, Beijing 100084, China;Center for Combustion Energy, Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China;

关键词: Particle-laden flows;    Turbulent flows;    Direct numerical simulations;    Particle tracking;   

DOI  :  

来源: DOAJ

【 摘 要 】

We successfully perform the three-dimensional tracking in a turbulent fluid flow of small axisymmetrical particles that are neutrally-buoyant and bottom-heavy, i.e., they have a non-homogeneous mass distribution along their symmetry axis. We experimentally show how a tiny mass inhomogeneity can affect the particle orientation along the preferred vertical direction and modify its tumbling rate. The experiment is complemented by a series of simulations based on realistic Navier–Stokes turbulence and on a point-like particle model that is capable to explore the full range of parameter space characterized by the gravitational torque stability number and by the particle aspect ratio. We propose a theoretical perturbative prediction valid in the high bottom-heaviness regime that agrees well with the observed preferential orientation and tumbling rate of the particles. We also show that the heavy-tail shape of the probability distribution function of the tumbling rate is weakly affected by the bottom-heaviness of the particles.

【 授权许可】

Unknown