Two-way coupling in particle-laden gas turbulence
Abstract
The goal of the proposed research is to critically advance our understanding of the effects of solid inertial particles on gas turbulence. In particular, we focus our attention on the cases in which: the gas flow is turbulent or transitional; the particles are smaller than the energetic flow scales; the particles are dilute; i.e. occupy a volume much smaller than the gas; the system is two-way coupled, i.e. both gas phase and particle phase influence each other. Those are relevant to a wealth of real-world situations, from sandstorms, to ocean spray, to ingestion of particulates in air-breathing engines, to inhalation of aerosol in the human airways. In those conditions, the fundamental question of whether particles enhance or reduce fluid turbulence, and under which conditions, remains open. To guide our investigation, we hypothesize that whether turbulence is augmented or suppressed depends on the translational and rotational slip being large or small, respectively; and that the extent of the modification depends on the mass loading. We further hypothesize that, contrary to the classic view but in line with more recent studies, the largest contribution to turbulence modification is due to particle clustering over large scales. To verify our hypotheses, we use novel and unique particle-laden flow facilities that produce two canonical configurations: a homogeneous turbulence chamber and a vertical channel flow. In them, we will consider three types of particles: spheres, fibers, and disks. Leveraging laser imaging, we make extensive use of particle image velocimetry (PIV) and particle tracking velocimetry (PTV) to simultaneously measure both the fluid flow motion and the inertial particle motion, at high spatial and temporal resolutions.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 14, 2019
- Source ID
- W911NF1810354
Entities
People
- Filippo Coletti
Organizations
- Army Contracting Command
- United States Army
- University of Minnesota