Effect of gravity on the development of homogeneous shear turbulence laden with finite-size particles

Tanaka, Mitsuru

doi:10.1080/14685248.2017.1363393

Cited by 17 publications

(25 citation statements)

References 48 publications

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“…García-Villalba et al 2012) have shown that wakes generated by small (d p /η 1) and large (d p /η 1) particles (with d p the particle diameter and η the Kolmogorov length scale) could have a direct contribution to the turbulent kinetic energy (TKE) production and dissipation even at low particle seedings. Tanaka (2017) performed fully resolved simulations of particle-laden homogeneous shear turbulence and showed that finite particle inertia generates mean slip velocities between the phases in both the streamwise and shear direction, resulting in a slower increase in fluid-phase TKE. When gravity is directed in the sheared direction, the Reynolds shear stress becomes relatively large between counter-rotating trailing vortices downstream of particles, which was found to contribute to a transient rapid increase in TKE (Tanaka 2017).…”

Section: Introductionmentioning

confidence: 99%

“…Tanaka (2017) performed fully resolved simulations of particle-laden homogeneous shear turbulence and showed that finite particle inertia generates mean slip velocities between the phases in both the streamwise and shear direction, resulting in a slower increase in fluid-phase TKE. When gravity is directed in the sheared direction, the Reynolds shear stress becomes relatively large between counter-rotating trailing vortices downstream of particles, which was found to contribute to a transient rapid increase in TKE (Tanaka 2017).…”

Section: Introductionmentioning

confidence: 99%

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On the transition between turbulence regimes in particle-laden channel flows

2018

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Turbulent wall-bounded flows exhibit a wide range of regimes with significant interaction between scales. The fluid dynamics associated with single-phase channel flows is predominantly characterized by the Reynolds number. Meanwhile, vastly different behaviour exists in particle-laden channel flows, even at a fixed Reynolds number. Vertical turbulent channel flows seeded with a low concentration of inertial particles are known to exhibit segregation in the particle distribution without significant modification to the underlying turbulent kinetic energy (TKE). At moderate (but still low) concentrations, enhancement or attenuation of fluid-phase TKE results from increased dissipation and wakes past individual particles. Recent studies have shown that denser suspensions significantly alter the two-phase dynamics, where the majority of TKE is generated by interphase coupling (i.e. drag) between the carrier gas and clusters of particles that fall near the channel wall. In the present study, a series of simulations of vertical particle-laden channel flows with increasing mass loading is conducted to analyse the transition from the dilute limit where classical mean-shear production is primarily responsible for generating fluid-phase TKE to high-mass-loading suspensions dominated by drag production. Eulerian–Lagrangian simulations are performed for a wide range of particle loadings at two values of the Stokes number, and the corresponding two-phase energy balances are reported to identify the mechanisms responsible for the observed transition.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

On the transition between turbulence regimes in particle-laden channel flows

2018

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“…The enhancement of the dissipation rate is more uniform around the surface of the oblates with a value of / sur ≈ 2.3 uniformly in all directions. Tanaka (2017) reported similar behaviour for the modulation of the production P and the dissipation rate in transient HST and dilute suspensions of spherical particles. More details of the origins of flow modulation by the solid phase can be obtained by the flow structures conditionally averaged around the surface of the particles.…”

Section: Flow Statistics Around Particlesmentioning

confidence: 58%

“…Numerical method The governing equations are solved numerically, using the method proposed by Gerz, Schumann & Elghobashi (1989), which employs the shear-periodic boundary condition. This was later modified by Tanaka (2017) to also handle the dispersed phase, using IBM, and is explained briefly here.…”

Section: Governing Equationsmentioning

confidence: 99%