Finite-size inertial spherical particles in turbulence

Abstract

We investigate by direct numerical simulations the fluid-solid interaction of non-dilute suspensions of spherical particles moving in triperiodic turbulence, at the relatively large Reynolds number of $R{e}_{\lambda }\approx 400$. The solid-to-fluid density ratio is varied between $1.3$ and $100$, the particle diameter $D$ ranges between $16\le D/\eta \le 123$ ($\eta$ is the Kolmogorov scale), and the volume fraction of the suspension is $0.079$. Turbulence is sustained using the Arnold-Beltrami-Childress cellular-flow forcing. The influence of the solid phase on the largest and energetic scales of the flow changes with the size and density of the particles. Light and large particles modulate all scales in a isotropic way, while heavier and smaller particles modulate the largest scales of the flow towards an anisotropic state. Smaller scales are isotropic and homogeneous for all cases. The mechanism driving the energy transfer across scales changes with the size and the density of the particles. For large and light particles the energy transfer is only marginally influenced by the fluid-solid interaction. For small and heavy particles, instead, the classical energy cascade is subdominant at all scales, and the energy transfer is essentially driven by the fluid-solid coupling. The influence of the solid phase on the flow intermittency is also discussed. Besides, the collective motion of the particles and their preferential location in relation with properties of the carrier flow are analysed. The solid phase exhibits moderate clustering; for large particles the level of clustering decreases with their density, while for small particles it is maximum for intermediate values.

References in corpus (17)

• An Immersed Boundary Method with Direct Forcing for the Simulation of Particulate Flows
• Interface-resolved DNS of vertical particulate channel flow in the turbulent regime
• Sedimentation of a dilute suspension of rigid spheres at intermediate Galileo numbers: the effect of clustering upon the particle motion
• DNS of horizontal open channel flow with finite-size, heavy particles at low solid volume fraction
• Experimental study of inertial particles clustering and settling in homogeneous turbulence
• Finite-size effects in the dynamics of neutrally buoyant particles in turbulent flow
• Turbulent fluid acceleration generates clusters of gyrotactic microorganisms
• Interface-resolved simulations of small inertial particles in turbulent channel flow
• On the clustering of finite-size particles in turbulence
• Mechanisms for the clustering of inertial particles in the inertial range of isotropic turbulence
• Distribution of relative velocities in turbulent aerosols
• Clustering and preferential concentration of finite-size particles in forced homogeneous-isotropic turbulence
• Near-wall turbulence modulation by small inertial particles
• Preferential concentration of free-falling heavy particles in turbulence
• The effect of particle anisotropy on the modulation of turbulent flows
• Attenuation of turbulence in a periodic cube by finite-size spherical solid particles
• Modulation of the regeneration cycle by neutrally buoyant finite-size particles