In this paper, Direct Numerical Simulation (DNS) and Lagrangian Particle Tracking are used to investigate dispersion and deposition of particles swarms in convective flow confined in a cylindrical domain with aspect ratio (diameter over height)0.5. The numerical simulations are carried out with Prandtl and Rayleigh numbers respectively equal to Pr = 0.7 and Ra= 2108. In this paper, Direct Numerical Simulation (DNS) and Lagrangian Particle Tracking are used to investigate dispersion and deposition of particles swarms in convective flow confined in a cylindrical domain with aspect ratio (diameter over height) 0.5. The numerical simulations are carried out with Prandtl and Rayleigh numbers respectively equal to Pr = 0.7 and Ra = 2108. For these values of aspect ratio, Rayleigh and Prandtl numbers the flow is turbulent and time-dependent. In such flow, three sets of particles with Stokes numbers, based on the large eddy time scale, equal to Stf = 0.01, St f = 0.005 and Stf = 0.001 are randomly dispersed. Particles distribution in turbulent convective flow is highly inhomogeneous and shows the clustering correlated with the vortical structures. The level of clustering is computed with the deviation of particles probability density function (PDF) from Poisson distribution. With this technique is available the size of the cluster but their geometry is unknown. The organisation along lines, planes and surfaces was investigated using the fractal dimension of the cluster. Finally, the flow topology is studied to relate the particles dispersion to coherent flow structures
Dispersion and Deposition of Particles in Rayleigh-Bénard Turbulent Flows / Oresta, Paolo; Lippolis, Antonio; Verzicco, Roberto; Soldati, Alfredo. - STAMPA. - (2006), pp. 1703-1713. (Intervento presentato al convegno 2nd US-European Fluids Engineering Division Summer Meeting/14th International Conference on Nuclear Engineering tenutosi a Miami, FL nel July 17-20, 2006) [10.1115/FEDSM2006-98243].
Dispersion and Deposition of Particles in Rayleigh-Bénard Turbulent Flows
Oresta, Paolo;Lippolis, Antonio;Verzicco, Roberto;
2006-01-01
Abstract
In this paper, Direct Numerical Simulation (DNS) and Lagrangian Particle Tracking are used to investigate dispersion and deposition of particles swarms in convective flow confined in a cylindrical domain with aspect ratio (diameter over height)0.5. The numerical simulations are carried out with Prandtl and Rayleigh numbers respectively equal to Pr = 0.7 and Ra= 2108. In this paper, Direct Numerical Simulation (DNS) and Lagrangian Particle Tracking are used to investigate dispersion and deposition of particles swarms in convective flow confined in a cylindrical domain with aspect ratio (diameter over height) 0.5. The numerical simulations are carried out with Prandtl and Rayleigh numbers respectively equal to Pr = 0.7 and Ra = 2108. For these values of aspect ratio, Rayleigh and Prandtl numbers the flow is turbulent and time-dependent. In such flow, three sets of particles with Stokes numbers, based on the large eddy time scale, equal to Stf = 0.01, St f = 0.005 and Stf = 0.001 are randomly dispersed. Particles distribution in turbulent convective flow is highly inhomogeneous and shows the clustering correlated with the vortical structures. The level of clustering is computed with the deviation of particles probability density function (PDF) from Poisson distribution. With this technique is available the size of the cluster but their geometry is unknown. The organisation along lines, planes and surfaces was investigated using the fractal dimension of the cluster. Finally, the flow topology is studied to relate the particles dispersion to coherent flow structuresI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.