scholarly journals Numerical Simulation for the Transport of Solid Particles with a Vortex Ring

2008 ◽  
Vol 45 (12) ◽  
pp. 827-834 ◽  
Author(s):  
Hisanori Yagami ◽  
Tomomi Uchiyama
Keyword(s):  
Numerical Simulation ◽  
Vortex Ring ◽  
Solid Particles

Numerical Simulation for the Collision of a Vortex Ring With Solid Particles

2007 ◽  
Author(s):  
Hisanori Yagami ◽  
Tomomi Uchiyama
Keyword(s):  
Numerical Simulation ◽  
Vortex Ring ◽  
Large Scale ◽  
Vortical Structure ◽  
Three Dimensional ◽  
Solid Particles ◽  
Convective Velocity ◽  
Centrifugal Effect ◽  
Small Glass ◽  
Induced Velocity

This study is concerned with the numerical simulation of the collision between a vortex ring and an ensemble of small glass particles. The vortex ring, convecting with the self-induced velocity in a quiescent air, collides with the particles. The Reynolds number for the vortex ring is 2600, and the particle diameters are 50 and 200μm. Immediately after the collision with the vortex ring, the 50μm particles surround the vortex ring, forming a dome. The 200μm particles disperse more due to the collision with the vortex ring. This is attributable to the centrifugal effect of the large-scale eddy. The collision between the vortex ring and the particles induces an organized three-dimensional vortical structure inside the vortex ring. It also reduces the strength of vortex ring and the convective velocity.

scholarly journals Numerical simulation of gas-solid flow in an interconnected fluidized bed

2015 ◽  
Vol 19 (1) ◽  
pp. 317-328 ◽  
Author(s):  
Giuseppe Canneto ◽  
Cesare Freda ◽  
Giacobbe Braccio
Keyword(s):  
Numerical Simulation ◽  
Fluidized Bed ◽  
Experimental Tests ◽  
Solid Particles ◽  
Multiphase Model ◽  
Cold Model ◽  
Conservation Equations ◽  
Solid Flow

The gas-particles flow in an interconnected bubbling fluidized cold model is simulated using a commercial CFD package by Ansys. Conservation equations of mass and momentum are solved using the Eulerian granular multiphase model. Bubbles formation and their paths are analyzed to investigate the behaviour of the bed at different gas velocities. Experimental tests, carried out by the cold model, are compared with simulation runs to study the fluidization quality and to estimate the circulation of solid particles in the bed.

Numerical simulation of hydraulic conveying of solid particles through a narrow elbow

2021 ◽  
Author(s):  
Elmar Anton Schnorr Filho ◽  
Nicolao Lima ◽  
Erick de Moraes Franklin
Keyword(s):  
Numerical Simulation ◽  
Solid Particles

scholarly journals Numerical stability analysis of a vortex ring with swirl

2019 ◽  
Vol 878 ◽  
pp. 5-36 ◽  
Author(s):  
Yuji Hattori ◽  
Francisco J. Blanco-Rodríguez ◽  
Stéphane Le Dizès
Keyword(s):  
Numerical Simulation ◽  
Growth Rate ◽  
Direct Numerical Simulation ◽  
Vortex Ring ◽  
Stokes Equations ◽  
Base Flow ◽  
Critical Layer ◽  
Navier Stokes ◽  
Instability Mode ◽  
Navier Stokes Equations

The linear instability of a vortex ring with swirl with Gaussian distributions of azimuthal vorticity and velocity in its core is studied by direct numerical simulation. The numerical study is carried out in two steps: first, an axisymmetric simulation of the Navier–Stokes equations is performed to obtain the quasi-steady state that forms a base flow; then, the equations are linearized around this base flow and integrated for a sufficiently long time to obtain the characteristics of the most unstable mode. It is shown that the vortex rings are subjected to curvature instability as predicted analytically by Blanco-Rodríguez & Le Dizès (J. Fluid Mech., vol. 814, 2017, pp. 397–415). Both the structure and the growth rate of the unstable modes obtained numerically are in good agreement with the analytical results. However, a small overestimation (e.g. 22 % for a curvature instability mode) by the theory of the numerical growth rate is found for some instability modes. This is most likely due to evaluation of the critical layer damping which is performed for the waves on axisymmetric line vortices in the analysis. The actual position of the critical layer is affected by deformation of the core due to the curvature effect; as a result, the damping rate changes since it is sensitive to the position of the critical layer. Competition between the curvature and elliptic instabilities is also investigated. Without swirl, only the elliptic instability is observed in agreement with previous numerical and experimental results. In the presence of swirl, sharp bands of both curvature and elliptic instabilities are obtained for $\unicode[STIX]{x1D700}=a/R=0.1$, where $a$ is the vortex core radius and $R$ the ring radius, while the elliptic instability dominates for $\unicode[STIX]{x1D700}=0.18$. New types of instability mode are also obtained: a special curvature mode composed of three waves is observed and spiral modes that do not seem to be related to any wave resonance. The curvature instability is also confirmed by direct numerical simulation of the full Navier–Stokes equations. Weakly nonlinear saturation and subsequent decay of the curvature instability are also observed.

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