Influence of gravitational settling on turbulent droplet clustering and radar reflectivity factor

Keigo Matsuda, Ryo Onishi, Keiko Takahashi

研究成果: Conference contribution

抄録

For radar cloud observations, the microwave refectivity of clouds is measured as the radar reflectivity factor Z, which is dependent on the cloud microphysical properties. Previous study has clarified that turbulent droplet clustering can be a cause of significant increase of the radar reflectivity factor. However, the influence of gravitational settling still remains to be clarified. This study, thus, investigates the influence of gravitational settling on the spatial distribution of turbulent clustering droplets and the radar reflectivity factor. A three-dimensional direct numerical simulation (DNS) of particle-laden isotropic turbulence is conducted for several values of the nondimensional terminal velocity Sv. The results show that the power spectrum of droplet number density fluctuation, which is calculated from the DNS data, depends on Sv as the droplet settling becomes stronger, the spectrum increases at small wavenumbers and decreases at large wavenumbers. The radar reflectivity factor Z is estimated from the power spectrum under ideal cloud conditions. The results indicate that the influence of turbulent clustering is suppressed under strong gravitational-settling conditions.

本文言語English
ホスト出版物のタイトル9th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2015
出版社TSFP-9
ISBN(電子版)9780000000002
出版ステータスPublished - 2015
外部発表はい
イベント9th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2015 - Melbourne, Australia
継続期間: 2015 6月 302015 7月 3

出版物シリーズ

名前9th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2015
3

Conference

Conference9th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2015
国/地域Australia
CityMelbourne
Period15/6/3015/7/3

ASJC Scopus subject areas

  • 流体および伝熱

フィンガープリント

「Influence of gravitational settling on turbulent droplet clustering and radar reflectivity factor」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。

引用スタイル