Droplet growth by gravitational coagulation enhanced by turbulence: Comparison of theory and measurements

Nicole Riemer, A. S. Wexler, K. Diehl

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

While it is well known that cloud droplets grow in an inherently turbulent environment, the role of turbulence is only now being elucidated. To shed light on this issue, we compare published measurements of droplet growth by collision in turbulent flow with numerical simulations. Because the measurements demonstrate an accelerated growth under turbulent conditions compared to laminar ones, the data clearly cannot be reproduced using the well-established kernel for sedimentation under laminar conditions. By employing a collision kernel that has been recently derived from direct numerical simulations, we perform sensitivity studies and quantify the parameter ranges that are compatible with the experimental data. This experiment does not enable us to uniquely determine the model parameters but we were able to place constraints on the form of acceptable models that reproduce the experimental data successfully. Moreover, we gain insight into how laboratory experiments could be improved to aid model validation.

Original languageEnglish (US)
Article numberD07204
JournalJournal of Geophysical Research: Atmospheres
Volume112
Issue number7
DOIs
StatePublished - Apr 16 2007

Fingerprint

coagulation
Coagulation
droplets
droplet
Turbulence
turbulence
turbulent flow
model validation
collision
seeds
collisions
cloud droplet
Direct numerical simulation
direct numerical simulation
Sedimentation
Turbulent flow
simulation
Experiments
sedimentation
sensitivity

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Atmospheric Science
  • Astronomy and Astrophysics
  • Oceanography

Cite this

Droplet growth by gravitational coagulation enhanced by turbulence : Comparison of theory and measurements. / Riemer, Nicole; Wexler, A. S.; Diehl, K.

In: Journal of Geophysical Research: Atmospheres, Vol. 112, No. 7, D07204, 16.04.2007.

Research output: Contribution to journalArticle

@article{efeb751727cf40059e0763dd6fb37b72,
title = "Droplet growth by gravitational coagulation enhanced by turbulence: Comparison of theory and measurements",
abstract = "While it is well known that cloud droplets grow in an inherently turbulent environment, the role of turbulence is only now being elucidated. To shed light on this issue, we compare published measurements of droplet growth by collision in turbulent flow with numerical simulations. Because the measurements demonstrate an accelerated growth under turbulent conditions compared to laminar ones, the data clearly cannot be reproduced using the well-established kernel for sedimentation under laminar conditions. By employing a collision kernel that has been recently derived from direct numerical simulations, we perform sensitivity studies and quantify the parameter ranges that are compatible with the experimental data. This experiment does not enable us to uniquely determine the model parameters but we were able to place constraints on the form of acceptable models that reproduce the experimental data successfully. Moreover, we gain insight into how laboratory experiments could be improved to aid model validation.",
author = "Nicole Riemer and Wexler, {A. S.} and K. Diehl",
year = "2007",
month = "4",
day = "16",
doi = "10.1029/2006JD007702",
language = "English (US)",
volume = "112",
journal = "Journal of Geophysical Research: Atmospheres",
issn = "0148-0227",
publisher = "American Geophysical Union",
number = "7",

}

TY - JOUR

T1 - Droplet growth by gravitational coagulation enhanced by turbulence

T2 - Comparison of theory and measurements

AU - Riemer, Nicole

AU - Wexler, A. S.

AU - Diehl, K.

PY - 2007/4/16

Y1 - 2007/4/16

N2 - While it is well known that cloud droplets grow in an inherently turbulent environment, the role of turbulence is only now being elucidated. To shed light on this issue, we compare published measurements of droplet growth by collision in turbulent flow with numerical simulations. Because the measurements demonstrate an accelerated growth under turbulent conditions compared to laminar ones, the data clearly cannot be reproduced using the well-established kernel for sedimentation under laminar conditions. By employing a collision kernel that has been recently derived from direct numerical simulations, we perform sensitivity studies and quantify the parameter ranges that are compatible with the experimental data. This experiment does not enable us to uniquely determine the model parameters but we were able to place constraints on the form of acceptable models that reproduce the experimental data successfully. Moreover, we gain insight into how laboratory experiments could be improved to aid model validation.

AB - While it is well known that cloud droplets grow in an inherently turbulent environment, the role of turbulence is only now being elucidated. To shed light on this issue, we compare published measurements of droplet growth by collision in turbulent flow with numerical simulations. Because the measurements demonstrate an accelerated growth under turbulent conditions compared to laminar ones, the data clearly cannot be reproduced using the well-established kernel for sedimentation under laminar conditions. By employing a collision kernel that has been recently derived from direct numerical simulations, we perform sensitivity studies and quantify the parameter ranges that are compatible with the experimental data. This experiment does not enable us to uniquely determine the model parameters but we were able to place constraints on the form of acceptable models that reproduce the experimental data successfully. Moreover, we gain insight into how laboratory experiments could be improved to aid model validation.

UR - http://www.scopus.com/inward/record.url?scp=34250303931&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=34250303931&partnerID=8YFLogxK

U2 - 10.1029/2006JD007702

DO - 10.1029/2006JD007702

M3 - Article

AN - SCOPUS:34250303931

VL - 112

JO - Journal of Geophysical Research: Atmospheres

JF - Journal of Geophysical Research: Atmospheres

SN - 0148-0227

IS - 7

M1 - D07204

ER -