Skip to main content Accesibility Help

Snowflakes in the atmospheric surface layer: observation of particle–turbulence dynamics

  • Andras Nemes (a1) (a2), Teja Dasari (a2) (a3), Jiarong Hong (a2) (a3), Michele Guala (a2) (a4) and Filippo Coletti (a1) (a2)...

We report on optical field measurements of snow settling in atmospheric turbulence at $Re_{\unicode[STIX]{x1D706}}=940$ . It is found that the snowflakes exhibit hallmark features of inertial particles in turbulence. The snow motion is analysed in both Eulerian and Lagrangian frameworks by large-scale particle imaging, while sonic anemometry is used to characterize the flow field. Additionally, the snowflake size and morphology are assessed by digital in-line holography. The low volume fraction and mass loading imply a one-way interaction with the turbulent air. Acceleration probability density functions show wide exponential tails consistent with laboratory and numerical studies of homogeneous isotropic turbulence. Invoking the assumption that the particle acceleration has a stronger dependence on the Stokes number than on the specific features of the turbulence (e.g. precise Reynolds number and large-scale anisotropy), we make inferences on the snowflakes’ aerodynamic response time. In particular, we observe that their acceleration distribution is consistent with that of particles of Stokes number in the range $St=0.1{-}0.4$ based on the Kolmogorov time scale. The still-air terminal velocities estimated for the resulting range of aerodynamic response times are significantly smaller than the measured snow particle fall speed. This is interpreted as a manifestation of settling enhancement by turbulence, which is observed here for the first time in a natural setting.

Corresponding author
Email address for correspondence:
Hide All
Aliseda, A., Cartellier, A., Hainaux, F. & Lasheras, J. C. 2002 Effect of preferential concentration on the settling velocity of heavy particles in homogeneous isotropic turbulence. J. Fluid Mech. 468, 77105.
Ayala, O., Rosa, B., Wang, L.-P. & Grabowski, W. W. 2008 Effects of turbulence on the geometric collision rate of sedimenting droplets. Part 1. Results from direct numerical simulation. New J. Phys. 10 (7), 075015.
Ayyalasomayajula, S., Gylfason, A., Collins, L. R., Bodenschatz, E. & Warhaft, Z. 2006 Lagrangian measurements of inertial particle accelerations in grid generated wind tunnel turbulence. Phys. Rev. Lett. 97 (14), 144507.
Beals, M. J., Fugal, J. P., Shaw, R. A., Lu, J., Spuler, S. M. & Stith, J. L. 2015 Holographic measurements of inhomogeneous cloud mixing at the centimeter scale. Science 350 (6256), 8790.
Bec, J., Biferale, L., Boffetta, G., Celani, A., Cencini, M., Lanotte, A., Musacchio, S. & Toschi, F. 2006 Acceleration statistics of heavy particles in turbulence. J. Fluid Mech. 550, 349358.
Bodenschatz, E., Malinowski, S. P., Shaw, R. A. & Stratmann, F. 2010 Can we understand clouds without turbulence? Science 327 (5968), 970971.
Böhm, H. P. 1989 A general equation for the terminal fall speed of solid hydrometeors. J. Atmos. Sci. 46 (15), 24192427.
Brandes, E. A., Ikeda, K., Zhang, G., Schönhuber, M. & Rasmussen, R. M. 2007 A statistical and physical description of hydrometeor distributions in Colorado snowstorms using a video disdrometer. J. Appl. Meteorol. Climatol. 46 (5), 634650.
Chun, J., Koch, D. L., Rani, S. L., Ahluwalia, A. & Collins, L. R. 2005 Clustering of aerosol particles in isotropic turbulence. J. Fluid Mech. 536, 219251.
Clift, R., Grace, J. R. & Weber, M. E. 2005 Bubbles, Drops, and Particles. Dover.
Clifton, A., Manes, C., Rüedi, J.-D., Guala, M. & Lehning, M. 2008 On shear-driven ventilation of snow. Boundary-Layer Meteorol. 126 (2), 249261.
Davila, J. & Hunt, J. C. R. 2001 Settling of small particles near vortices and in turbulence. J. Fluid Mech. 440, 117145.
Dejoan, A. & Monchaux, R. 2013 Preferential concentration and settling of heavy particles in homogeneous turbulence. Phys. Fluids 25 (1), 013301.
Ditas, F., Shaw, R. A., Siebert, H., Simmel, M., Wehner, B. & Wiedensohler, A. 2012 Aerosols-cloud microphysics-thermodynamics-turbulence: evaluating supersaturation in a marine stratocumulus cloud. Atmos. Chem. Phys. 12 (5), 24592468.
Eaton, J. K. & Fessler, J. R. 1994 Preferential concentration of particles by turbulence. Intl J. Multiphase Flow 20, 169209.
Elghobashi, S. 1994 On predicting particle-laden turbulent flows. Appl. Sci. Res. 52 (4), 309329.
Elghobashi, S. & Truesdell, G. C. 1992 Direct simulation of particle dispersion in a decaying isotropic turbulence. J. Fluid Mech. 242, 655700.
Elghobashi, S. & Truesdell, G. C. 1993 On the two-way interaction between homogeneous turbulence and dispersed solid particles. I. Turbulence modification. Phys. Fluids A 5 (7), 17901801.
Falkovich, G., Fouxon, A. & Stepanov, M. G. 2002 Acceleration of rain initiation by cloud turbulence. Nature 419 (6903), 151154.
Ferrante, A. & Elghobashi, S. 2003 On the physical mechanisms of two-way coupling in particle-laden isotropic turbulence. Phys. Fluids 15 (2), 315329.
Fouras, A., Lo Jacono, D. & Hourigan, K. 2008 Target-free stereo PIV: a novel technique with inherent error estimation and improved accuracy. Exp. Fluids 44, 317329.
Fugal, J. P., Schulz, T. J. & Shaw, R. A. 2009 Practical methods for automated reconstruction and characterization of particles in digital in-line holograms. Meas. Sci. Technol. 20 (7), 075501.
Garrett, T. J. & Yuter, S. E. 2014 Observed influence of riming, temperature, and turbulence on the fallspeed of solid precipitation. Geophys. Res. Lett. 41 (18), 65156522.
Gerashchenko, S., Sharp, N. S., Neuscamman, S. & Warhaft, Z. 2008 Lagrangian measurements of inertial particle accelerations in a turbulent boundary layer. J. Fluid Mech. 617, 255281.
Good, G. H., Ireland, P. J., Bewley, G. P., Bodenschatz, E., Collins, L. R. & Warhaft, Z. 2014 Settling regimes of inertial particles in isotropic turbulence. J. Fluid Mech. 759, R3.
Grabowski, W. W. & Wang, L.-P. 2013 Growth of cloud droplets in a turbulent environment. Annu. Rev. Fluid Mech. 45, 293324.
Guala, M., Metzger, M. & McKeon, B. J. 2010 Intermittency in the atmospheric surface layer: unresolved or slowly varying? Physica D 239 (14), 12511257.
Gulitski, G., Kholmyansky, M., Kinzelbach, W., Lüthi, B., Tsinober, A. & Yorish, S. 2007 Velocity and temperature derivatives in high-Reynolds-number turbulent flows in the atmospheric surface layer. Part 2. Accelerations and related matters. J. Fluid Mech. 589, 83102.
Gylfason, A., Ayyalasomayajula, S. & Warhaft, Z. 2004 Intermittency, pressure and acceleration statistics from hot-wire measurements in wind-tunnel turbulence. J. Fluid Mech. 501, 213229.
Heymsfield, A. J., Bansemer, A., Schmitt, C., Twohy, C. & Poellot, M. R. 2004 Effective ice particle densities derived from aircraft data. J. Atmos. Sci. 61 (9), 9821003.
Heymsfield, A. J. & Westbrook, C. D. 2010 Advances in the estimation of ice particle fall speeds using laboratory and field measurements. J. Atmos. Sci. 67 (8), 24692482.
Hong, J., Toloui, M., Chamorro, L. P., Guala, M., Howard, K., Riley, S., Tucker, J. & Sotiropoulos, F. 2014 Natural snowfall reveals large-scale flow structures in the wake of a 2.5-MW wind turbine. Nat. Commun. 5, 4216.
Howard, K. B. & Guala, M. 2016 Upwind preview to a horizontal axis wind turbine: a wind tunnel and field-scale study. Wind Energy 19, 13711389.
Hutchins, N., Chauhan, K., Marusic, I., Monty, J. & Klewicki, J. 2012 Towards reconciling the large-scale structure of turbulent boundary layers in the atmosphere and laboratory. Boundary-Layer Met. 145 (2), 273306.
Ireland, P. J., Bragg, A. D. & Collins, L. R. 2016a The effect of Reynolds number on inertial particle dynamics in isotropic turbulence. Part 1. Simulations without gravitational effects. J. Fluid Mech. 796, 617658.
Ireland, P. J., Bragg, A. D. & Collins, L. R. 2016b The effect of Reynolds number on inertial particle dynamics in isotropic turbulence. Part 2. Simulations with gravitational effects. J. Fluid Mech. 796, 659711.
Ishihara, T., Kaneda, Y., Yokokawa, M., Itakura, K. & Uno, A. 2007 Small-scale statistics in high-resolution direct numerical simulation of turbulence: Reynolds number dependence of one-point velocity gradient statistics. J. Fluid Mech. 592, 335366.
Katz, J. & Sheng, J. 2010 Applications of holography in fluid mechanics and particle dynamics. Annu. Rev. Fluid Mech. 42, 531555.
Klewicki, J. C., Metzger, M. M., Kelner, E. & Thurlow, E. M. 1995 Viscous sublayer flow visualizations at R 𝜃≅1 500 000. Phys. Fluids 7 (4), 857863.
Kolmogorov, A. N. 1962 A refinement of previous hypotheses concerning the local structure of turbulence in a viscous incompressible fluid at high Reynolds number. J. Fluid Mech. 13 (01), 8285.
Kunkel, G. J. & Marusic, I. 2006 Study of the near-wall-turbulent region of the high-Reynolds-number boundary layer using an atmospheric flow. J. Fluid Mech. 548, 375402.
Locatelli, J. D. & Hobbs, P. V. 1974 Fall speeds and masses of solid precipitation particles. J. Geophys. Res. 79 (15), 21852197.
Matsuda, K., Onishi, R., Hirahara, M., Kurose, R., Takahashi, K. & Komori, S. 2014 Influence of microscale turbulent droplet clustering on radar cloud observations. J. Atmos. Sci. 71 (10), 35693582.
Maxey, M. R. 1987 The gravitational settling of aerosol particles in homogeneous turbulence and random flow fields. J. Fluid Mech. 174, 441465.
Melling, A. 1997 Tracer particles and seeding for particle image velocimetry. Meas. Sci. Technol. 8 (12), 1406.
Mitchell, D. L. 1996 Use of mass-and area-dimensional power laws for determining precipitation particle terminal velocities. J. Atmos. Sci. 53 (12), 17101723.
Monchaux, R., Bourgoin, M. & Cartellier, A. 2010 Preferential concentration of heavy particles: a Voronoï analysis. Phys. Fluids 22 (10), 103304.
Mordant, N., Crawford, A. M. & Bodenschatz, E. 2004 Experimental Lagrangian acceleration probability density function measurement. Physica D 193 (1), 245251.
Morris, S. C., Stolpa, S. R., Slaboch, P. E. & Klewicki, J. C. 2007 Near-surface particle image velocimetry measurements in a transitionally rough-wall atmospheric boundary layer. J. Fluid Mech. 580, 319338.
Ouellette, N. T., Xu, H. & Bodenschatz, E. 2006 A quantitative study of three-dimensional Lagrangian particle tracking algorithms. Exp. Fluids 40 (2), 301313.
Pruppacher, H. R. & Klett, J. D. 1997 Microphysics of Clouds and Precipitation. Springer.
Rosa, B., Parishani, H., Ayala, O. & Wang, L.-P. 2016 Settling velocity of small inertial particles in homogeneous isotropic turbulence from high-resolution DNS. Intl J. Multiphase Flow 83, 217231.
Saddoughi, S. G. & Veeravalli, S. V. 1994 Local isotropy in turbulent boundary layers at high Reynolds number. J. Fluid Mech. 268, 333372.
Salazar, J. P. L. C. & Collins, L. R. 2012 Inertial particle acceleration statistics in turbulence: effects of filtering, biased sampling, and flow topology. Phys. Fluids 24 (8), 083302.
Shaw, R. A. 2003 Particle-turbulence interactions in atmospheric clouds. Annu. Rev. Fluid Mech. 35 (1), 183227.
Shaw, R. A. & Oncley, S. P. 2001 Acceleration intermittency and enhanced collision kernels in turbulent clouds. Atmos. Res. 59, 7787.
Siebert, H., Gerashchenko, S., Gylfason, A., Lehmann, K., Collins, L. R., Shaw, R. A. & Warhaft, Z. 2010 Towards understanding the role of turbulence on droplets in clouds: in situ and laboratory measurements. Atmos. Res. 97 (4), 426437.
Siebert, H., Shaw, R. A., Ditas, J., Schmeissner, T., Malinowski, S. P., Bodenschatz, E. & Xu, H. 2015 High-resolution measurement of cloud microphysics and turbulence at a mountaintop station. Atmos. Meas. Tech. 8 (8), 32193228.
Squires, K. D. & Eaton, J. K. 1990 Particle response and turbulence modification in isotropic turbulence. Phys. Fluids A 2 (7), 11911203.
Squires, K. D. & Eaton, J. K. 1991 Preferential concentration of particles by turbulence. Phys. Fluids 3 (5), 11691178.
Sundaram, S. & Collins, L. R. 1997 Collision statistics in an isotropic particle-laden turbulent suspension. Part 1. Direct numerical simulations. J. Fluid Mech. 335, 75109.
Talapatra, S., Hong, J., McFarland, M., Nayak, A. R., Zhang, C., Katz, J., Sullivan, J., Twardowski, M., Rines, J. & Donaghay, P. 2013 Characterization of biophysical interactions in the water column using in situ digital holography. Mar. Ecol. Progress Series 473, 2951.
Thompson, G., Field, P. R., Rasmussen, R. M. & Hall, W. D. 2008 Explicit forecasts of winter precipitation using an improved bulk microphysics scheme. Part II. Implementation of a new snow parameterization. Mon. Weath. Rev. 136 (12), 50955115.
Toloui, M., Riley, S., Hong, J., Howard, K., Chamorro, L. P., Guala, M. & Tucker, J. 2014 Measurement of atmospheric boundary layer based on super-large-scale particle image velocimetry using natural snowfall. Exp. Fluids 55 (5), 114.
Toschi, F. & Bodenschatz, E. 2009 Lagrangian properties of particles in turbulence. Annu. Rev. Fluid Mech. 41, 375404.
Townsend, A. A. 1980 The Structure of Turbulent Shear Flow. Cambridge University Press.
Voth, G. A., la Porta, A., Crawford, A. M., Alexander, J. & Bodenschatz, E. 2002 Measurement of particle accelerations in fully developed turbulence. J. Fluid Mech. 469, 121160.
Wang, L.-P. & Maxey, M. R. 1993 Settling velocity and concentration distribution of heavy particles in homogeneous isotropic turbulence. J. Fluid Mech. 256, 2768.
Wang, L.-P., Wexler, A. S. & Zhou, Y. 2000 Statistical mechanical description and modelling of turbulent collision of inertial particles. J. Fluid Mech. 415, 117153.
Westerweel, J. & Scarano, F. 2005 Universal outlier detection for PIV data. Exp. Fluids 39 (6), 10961100.
Wood, A. M., Hwang, W. & Eaton, J. K. 2005 Preferential concentration of particles in homogeneous and isotropic turbulence. Intl J. Multiphase Flow 31 (10), 12201230.
Yang, C. Y. & Lei, U. 1998 The role of the turbulent scales in the settling velocity of heavy particles in homogeneous isotropic turbulence. J. Fluid Mech. 371, 179205.
Yang, T.-S. & Shy, S. S. 2005 Two-way interaction between solid particles and homogeneous air turbulence: particle settling rate and turbulence modification measurements. J. Fluid Mech. 526, 171216.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Journal of Fluid Mechanics
  • ISSN: 0022-1120
  • EISSN: 1469-7645
  • URL: /core/journals/journal-of-fluid-mechanics
Please enter your name
Please enter a valid email address
Who would you like to send this to? *

JFM classification


Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed