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Rotation of Nonspherical Particles in Turbulent Channel Flow
Lihao Zhao1, Niranjan Reddy Challabotla1, Helge I Andersson1
1Department of Energy and Process Engineering, Norwegian University of Science and Technology, 7491 Trondheim, Norway.
Physical Review Letters
|December 27, 2015
Summary
Particle rotation in turbulent flow depends on shape and inertia. Inertia affects oblate and prolate particles differently near channel walls versus the center, influenced by fluid shear.
Area of Science:
- Fluid dynamics
- Turbulence research
- Particle transport
Background:
- Understanding particle behavior in turbulent flows is crucial for various applications.
- Particle rotation is influenced by fluid shear, inertia, and particle shape.
- Turbulent channel flow presents distinct regions of isotropic and sheared turbulence.
Purpose of the Study:
- To investigate the effects of particle inertia, shape, and fluid shear on particle rotation.
- To compare particle rotation patterns in isotropic versus sheared turbulent regions.
- To elucidate the role of preferential orientation in observed rotational behaviors.
Main Methods:
- Direct numerical simulation (DNS) of turbulent channel flow.
- Analysis of particle rotation dynamics for oblate and prolate spheroids.
- Examination of particle behavior at the channel center and near the wall.
Main Results:
- Particle rotation patterns differ significantly between the channel center and near the wall.
- Increasing particle inertia alters rotation trends, particularly for oblate particles at the center.
- Near the wall, inertia reverses the typical rotation trends for both oblate and prolate spheroids.
- Observed phenomena are largely attributed to preferential particle orientations.
Conclusions:
- Particle inertia and fluid shear interact complexly to dictate particle rotation in turbulent flows.
- The location within the turbulent channel (center vs. wall) critically influences how inertia affects particle rotation.
- Preferential orientation is a key mechanism governing the rotational dynamics of non-spherical particles in turbulence.
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