Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Effect of turbulence on collisional growth of cloud droplets
Stockholm University, Faculty of Science, Department of Meteorology . Stockholm University, Nordic Institute for Theoretical Physics (Nordita). Swedish e-Science Research Centre, Sweden; University of Colorado, USA.ORCID iD: 0000-0002-5722-0018
Stockholm University, Nordic Institute for Theoretical Physics (Nordita). Stockholm University, Faculty of Science, Department of Astronomy. University of Colorado, USA.
Stockholm University, Faculty of Science, Department of Meteorology . Swedish e-Science Research Centre, Sweden; Global & Climate Dynamics, National Center for Atmospheric Research, USA.
Show others and affiliations
2018 (English)In: Journal of Atmospheric Sciences, ISSN 0022-4928, E-ISSN 1520-0469Article in journal (Refereed) Epub ahead of print
Abstract [en]

We investigate the effect of turbulence on the collisional growth of um-sized droplets through high- resolution numerical simulations with well resolved Kolmogorov scales, assuming a collision and coalescence efficiency of unity. The droplet dynamics and collisions are approximated using a superparticle approach. In the absence of gravity, we show that the time evolution of the shape of the droplet-size distribution due to turbulence-induced collisions depends strongly on the turbulent energy-dissipation rate, but only weakly on the Reynolds number. This can be explained through the energy dissipation rate dependence of the mean collision rate described by the Saffman-Turner collision model. Consistent with the Saffman-Turner collision model and its extensions, the collision rate increases as the square root of the energy dissipation rate even when coalescence is invoked. The size distribution exhibits power law behavior with a slope of -3.7 between a maximum at approximately 10 um up to about 40 um. When gravity is invoked, turbulence is found to dominate the time evolution of an initially monodisperse droplet distribution at early times. At later times, however, gravity takes over and dominates the collisional growth. We find that the formation of large droplets is very sensitive to the turbulent energy dissipation rate. This is due to the fact that turbulence enhances the collisional growth between similar sized droplets at the early stage of raindrop formation. The mean collision rate grows exponentially, which is consistent with the theoretical prediction of the continuous collisional growth even when turbulence-generated collisions are invoked. This consistency only reflects the mean effect of turbulence on collisional growth.

Place, publisher, year, edition, pages
2018.
National Category
Climate Research
Research subject
Atmospheric Sciences and Oceanography
Identifiers
URN: urn:nbn:se:su:diva-158534DOI: 10.1175/JAS-D-18-0081.1OAI: oai:DiVA.org:su-158534DiVA, id: diva2:1237401
Funder
The Research Council of Norway, FRINATEK grant 231444Swedish Research Council, 2012-5797; 2013-03992Knut and Alice Wallenberg Foundation, Dnr. KAW 2014.0048Available from: 2018-08-08 Created: 2018-08-08 Last updated: 2018-08-15
In thesis
1.
The record could not be found. The reason may be that the record is no longer available or you may have typed in a wrong id in the address field.

Open Access in DiVA

No full text in DiVA

Other links

Publisher's full textarXiv:1711.10062

Search in DiVA

By author/editor
Li, Xiang-YuBrandenburg, AxelSvensson, Gunilla
By organisation
Department of Meteorology Nordic Institute for Theoretical Physics (Nordita)Department of Astronomy
In the same journal
Journal of Atmospheric Sciences
Climate Research

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 4 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf