Turbulent pair dispersion in the presence of gravity
Turbulent pair dispersion of heavy particles is strongly altered when particles of two different Stokes numbers (bidisperse) are considered, and this is further compounded when a uniform gravitational acceleration is present. Lagrangian trajectories of fluid tracers, and bidisperse heavy particles w...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2015-01-01
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| Series: | New Journal of Physics |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1367-2630/17/3/033010 |
| _version_ | 1797751188660158464 |
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| author | Kelken Chang Benedict J Malec Raymond A Shaw |
| author_facet | Kelken Chang Benedict J Malec Raymond A Shaw |
| author_sort | Kelken Chang |
| collection | DOAJ |
| description | Turbulent pair dispersion of heavy particles is strongly altered when particles of two different Stokes numbers (bidisperse) are considered, and this is further compounded when a uniform gravitational acceleration is present. Lagrangian trajectories of fluid tracers, and bidisperse heavy particles with and without gravity were calculated from a direct numerical simulation of homogeneous, isotropic turbulence. Particle pair dispersion shows a short-time, ballistic (Batchelor) regime and a transition to super-ballistic dispersion that is suggestive of the emergence of Richardson scaling. A simple equation of motion for inertial, sedimenting particles captures the essential features of the pair dispersion at very short time and length scales. Kolmogorov scaling arguments are able to qualitatively describe the competition between gravity-induced and fluid-induced relative motion in modifying the amount of time the heavy particles spend in the ballistic regime. The transition from ballistic to super-ballistic dispersion for fluid tracers and monodisperse inertial particles exhibits a pronounced sub-ballistic behavior that can be attributed to the mixed velocity–acceleration structure function. The sub-ballistic behavior is strongly suppressed for bidisperse particles, both in the presence or absence of gravity, primarily because of a reduction in the correlation between velocity and acceleration increments. |
| first_indexed | 2024-03-12T16:44:53Z |
| format | Article |
| id | doaj.art-c3619b56e9c34991a1fd29eee2271437 |
| institution | Directory Open Access Journal |
| issn | 1367-2630 |
| language | English |
| last_indexed | 2024-03-12T16:44:53Z |
| publishDate | 2015-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | New Journal of Physics |
| spelling | doaj.art-c3619b56e9c34991a1fd29eee22714372023-08-08T14:18:10ZengIOP PublishingNew Journal of Physics1367-26302015-01-0117303301010.1088/1367-2630/17/3/033010Turbulent pair dispersion in the presence of gravityKelken Chang0Benedict J Malec1Raymond A Shaw2Department of Physics, Michigan Technological UniversityDepartment of Physics, Michigan Technological UniversityDepartment of Physics, Michigan Technological UniversityTurbulent pair dispersion of heavy particles is strongly altered when particles of two different Stokes numbers (bidisperse) are considered, and this is further compounded when a uniform gravitational acceleration is present. Lagrangian trajectories of fluid tracers, and bidisperse heavy particles with and without gravity were calculated from a direct numerical simulation of homogeneous, isotropic turbulence. Particle pair dispersion shows a short-time, ballistic (Batchelor) regime and a transition to super-ballistic dispersion that is suggestive of the emergence of Richardson scaling. A simple equation of motion for inertial, sedimenting particles captures the essential features of the pair dispersion at very short time and length scales. Kolmogorov scaling arguments are able to qualitatively describe the competition between gravity-induced and fluid-induced relative motion in modifying the amount of time the heavy particles spend in the ballistic regime. The transition from ballistic to super-ballistic dispersion for fluid tracers and monodisperse inertial particles exhibits a pronounced sub-ballistic behavior that can be attributed to the mixed velocity–acceleration structure function. The sub-ballistic behavior is strongly suppressed for bidisperse particles, both in the presence or absence of gravity, primarily because of a reduction in the correlation between velocity and acceleration increments.https://doi.org/10.1088/1367-2630/17/3/033010turbulenceinertial particlesnumerical simulations |
| spellingShingle | Kelken Chang Benedict J Malec Raymond A Shaw Turbulent pair dispersion in the presence of gravity New Journal of Physics turbulence inertial particles numerical simulations |
| title | Turbulent pair dispersion in the presence of gravity |
| title_full | Turbulent pair dispersion in the presence of gravity |
| title_fullStr | Turbulent pair dispersion in the presence of gravity |
| title_full_unstemmed | Turbulent pair dispersion in the presence of gravity |
| title_short | Turbulent pair dispersion in the presence of gravity |
| title_sort | turbulent pair dispersion in the presence of gravity |
| topic | turbulence inertial particles numerical simulations |
| url | https://doi.org/10.1088/1367-2630/17/3/033010 |
| work_keys_str_mv | AT kelkenchang turbulentpairdispersioninthepresenceofgravity AT benedictjmalec turbulentpairdispersioninthepresenceofgravity AT raymondashaw turbulentpairdispersioninthepresenceofgravity |