Anisotropic turbulent clustering mechanism of gravitational-settling spherical and nonspherical inertial particles

• Project/Area Number: 17K14598
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Fluid engineering
• Research Institution: Japan Agency for Marine-Earth Science and Technology
• Principal Investigator: Matsuda Keigo 国立研究開発法人海洋研究開発機構, 付加価値情報創生部門(地球情報基盤センター), 研究員 (50633880)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000); Fiscal Year 2019: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2018: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2017: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
• Keywords: 乱流 / 混相流 / 雲 / 直接数値シミュレーション / レーダー観測 / 雲乱流 / レーダー反射強度 / 乱流クラスタリング / レーダ反射強度 / 流体工学 / リモートセンシング

Outline of Final Research Achievements

Effects of nonuniform cloud particle distribution in turbulence (turbulent clustering) on increase of the radar reflectivity in cloud observations were investigated using a direct numerical simulation of particle-laden turbulence. A model to predict the increase of radar reflectivity was developed considering the influence of gravitational settling and polydisperse particle sizes, and the effects of turbulent clustering in radar observations of realistic convective clouds were presented quantitatively. In addition, the effects of turbulent clustering of ice particles (non-spherical particles) were clarified.

Academic Significance and Societal Importance of the Research Achievements

本研究により，雲粒子の乱流クラスタリングによるレーダー反射因子の増加量を定量的に推定することが可能となった．本研究で構築したモデル式を応用することでレーダー観測によって対流雲中の乱流状態を推定できる可能性がある．対流雲中の乱流は衝突併合による雲粒の成長を促進させることから，レーダー観測によって対流雲中の乱流状態を推定することにより，突発的豪雨の早期検知に役立つ可能性が期待される．

Research Products

• [Int'l Joint Research] Aix-Marseille University(フランス)
• [Int'l Joint Research] Aix-Marseille University(フランス)
• [Journal Article] Turbulent enhancement of radar reflectivity factor for polydisperse cloud droplets (2019)
  • Author(s): Matsuda Keigo、Onishi Ryo
  • Journal Title: Atmospheric Chemistry and Physics Volume: 19 Issue: 3 Pages: 1785-1799
  • DOI: 10.5194/acp-19-1785-2019
  • Peer Reviewed / Open Access
• [Journal Article] Turbulent enhancement of radar reflectivity factor for polydisperse cloud droplets (2018)
  • Author(s): Matsuda Keigo、Onishi Ryo
  • Journal Title: Atmospheric Chemistry and Physics Discussions Volume: - Pages: 1-21
  • DOI: 10.5194/acp-2018-480
  • Peer Reviewed / Open Access
• [Journal Article] Scale-similar clustering of heavy particles in the inertial range of turbulence (2018)
  • Author(s): T. Ariki, K. Yoshida, K. Matsuda and K. Yoshimatsu
  • Journal Title: Physical Review E Volume: 97 Issue: 3 Pages: 033109-033109
  • DOI: 10.1103/physreve.97.033109
  • NAID: 120007133868
  • Peer Reviewed
• [Presentation] Enhancement of radar reflectivity factor due to turbulent droplet clustering in cumulus clouds (2019)
  • Author(s): K. Matsuda, R. Onishi
  • Organizer: Workshop on Eulerian vs. Lagrangian methods for cloud microphysics
  • Int'l Joint Research
• [Presentation] Intermittency of inertial particle distribution in high Reynolds number turbulence (2019)
  • Author(s): K. Matsuda, K. Schneider, K. Yoshimatsu
  • Organizer: 17th European Turbulence Conference (ETC17)
  • Int'l Joint Research
• [Presentation] Inertial particle distribution in high Reynolds number turbulence: wavelet-based scale-dependent statistics (2019)
  • Author(s): K. Matsuda, K. Schneider, K. Yoshimatsu
  • Organizer: 72nd Annual Meeting of the American Physical Society Division of Fluid Dynamics (APS/DFD 2019)
  • Int'l Joint Research
• [Presentation] Divergence and convergence of inertial particles in high Reynolds number turbulence (2019)
  • Author(s): Thibault Oujia, Keigo Matsuda, Kai Schneider
  • Organizer: 72nd Annual Meeting of the American Physical Society Division of Fluid Dynamics (APS/DFD 2019)
  • Int'l Joint Research
• [Presentation] Statistical modeling of inertial droplet clustering in cloud turbulence (2019)
  • Author(s): K. Matsuda
  • Organizer: International Workshop on Multiphase Turbulence and Statistical Modeling
  • Int'l Joint Research
• [Presentation] Scale-dependent and directional statistics of inertial particle clustering in high Reynolds number turbulence using wavelet analysis (2019)
  • Author(s): K. Matsuda
  • Organizer: Workshop on Wavelet & CFD
  • Int'l Joint Research
• [Presentation] Multiscale analyses of inertial particle clustering in homogeneous isotropic turbulence (2019)
  • Author(s): K. Matsuda, K. Schneider, K. Yoshimatsu
  • Organizer: 4th International Workshop on Marine-Earth Science Simulations: Data assimilation and multiscale techniques for numerical simulation of turbulent flows
  • Int'l Joint Research
• [Presentation] Wavelet-based multiscale analyses of inertial particle distribution in homogeneous isotropic turbulence (2019)
  • Author(s): K. Matsuda, K. Schneider, K. Yoshimatsu
  • Organizer: French-Japanese Workshop on Wavelet and Large Eddy Representations to Study Turbulent Flows
  • Int'l Joint Research
• [Presentation] 雲粒の乱流クラスタリングによる雲レーダー反射強度増強効果のモデル化：粒径分布および重力沈降の影響 (2019)
  • Author(s): 松田景吾, 大西 領
  • Organizer: 日本流体力学会年会2019
• [Presentation] Radar reflectivity factor enhancement due to microscale turbulent clustering of polydispersed cloud droplets (2018)
  • Author(s): Matsuda Keigo、Onishi Ryo
  • Organizer: AMS 15th Conference on Cloud Physics/ 15th Conference on Atmospheric Radiation
  • Int'l Joint Research
• [Presentation] Cloud radar reflectivity factor enhancement due to turbulent droplet clustering (2018)
  • Author(s): Matsuda Keigo、Onishi Ryo
  • Organizer: GDR Turbulence Meeting
  • Int'l Joint Research
• [Presentation] Numerical study on cloud radar reflectivity enhancement due to turbulent droplet clustering (2018)
  • Author(s): K. Matsuda
  • Organizer: NITech Lectures on Turbulence and Cloud
  • Int'l Joint Research / Invited
• [Presentation] Enhancement of cloud radar reflectivity factor due to turbulent clustering of settling water droplets (2017)
  • Author(s): K. Matsuda, R. Onishi, K. Takahashi
  • Organizer: Turbulence Conference at Mauna Kea (TCM2017): Recent advances in turbulence research, 98th Annual Meeting of the American Association for the Advancement of Science (AAAS) Pacific Division
  • Int'l Joint Research
• [Presentation] Multiscale turbulent clustering of bidispersed inertial particles in isotropic turbulence (2017)
  • Author(s): K. Matsuda, R. Onishi, K. Takahashi
  • Organizer: 16th European Turbulence Conference
  • Int'l Joint Research
• [Presentation] Scale similarity of the particle clustering in the inertial range of turbulence (2017)
  • Author(s): T. Ariki, K. Yoshida, K. Matsuda, K. Yoshimatsu
  • Organizer: Turbulence Conference at Mauna Kea (TCM2017): Recent advances in turbulence research, 98th Annual Meeting of the American Association for the Advancement of Science (AAAS) Pacific Division
  • Int'l Joint Research
• [Presentation] 乱流慣性領域中の粒子クラスタリング (2017)
  • Author(s): 有木健人, 吉田 恭, 松田景吾, 芳松克則
  • Organizer: 数理解析研究所研究集会「非一様乱流の数理」