Wake-Driven Dynamics of Finite-Sized Buoyant Spheres in Turbulence.

Autor:	Mathai V; Physics of Fluids Group, Faculty of Science and Technology, J. M. Burgers Centre for Fluid Dynamics, University of Twente, P.O. Box 217, 7500 AE Enschede, Netherlands., Prakash VN; Physics of Fluids Group, Faculty of Science and Technology, J. M. Burgers Centre for Fluid Dynamics, University of Twente, P.O. Box 217, 7500 AE Enschede, Netherlands.; Department of Bioengineering, Stanford University, Stanford, California 94305, USA., Brons J; Physics of Fluids Group, Faculty of Science and Technology, J. M. Burgers Centre for Fluid Dynamics, University of Twente, P.O. Box 217, 7500 AE Enschede, Netherlands., Sun C; Physics of Fluids Group, Faculty of Science and Technology, J. M. Burgers Centre for Fluid Dynamics, University of Twente, P.O. Box 217, 7500 AE Enschede, Netherlands.; Center for Combustion Energy and Department of Thermal Engineering, Tsinghua University, 100084 Beijing, China., Lohse D; Physics of Fluids Group, Faculty of Science and Technology, J. M. Burgers Centre for Fluid Dynamics, University of Twente, P.O. Box 217, 7500 AE Enschede, Netherlands.
Jazyk:	angličtina
Zdroj:	Physical review letters [Phys Rev Lett] 2015 Sep 18; Vol. 115 (12), pp. 124501. Date of Electronic Publication: 2015 Sep 17.
DOI:	10.1103/PhysRevLett.115.124501
Abstrakt:	Particles suspended in turbulent flows are affected by the turbulence and at the same time act back on the flow. The resulting coupling can give rise to rich variability in their dynamics. Here we report experimental results from an investigation of finite-sized buoyant spheres in turbulence. We find that even a marginal reduction in the particle's density from that of the fluid can result in strong modification of its dynamics. In contrast to classical spatial filtering arguments and predictions of particle models, we find that the particle acceleration variance increases with size. We trace this reversed trend back to the growing contribution from wake-induced forces, unaccounted for in current particle models in turbulence. Our findings highlight the need for improved multiphysics based models that account for particle wake effects for a faithful representation of buoyant-sphere dynamics in turbulence.
Databáze:	MEDLINE
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