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Mechanics of the granular rapid subaerial flow(pyroclastic flow and snow avalanche)

Research Project

Project/Area Number 08458102
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field Natural disaster science
Research InstitutionKYOTO UNIVERSITY

Principal Investigator

TAKAHASHI Tamotsu  Kyoto University, Disaster Prevention Research Inst.Professor, 防災研究所, 教授 (40027230)

Co-Investigator(Kenkyū-buntansha) SATOFUKA Yoshifumi  Kyoto University, Disaster Prevention Research Inst.Instructor, 防災研究所, 助手 (20215875)
NAKAGAWA Hajime  Kyoto University, Disaster Prevention Research Inst.Assoc.Professor, 防災研究所, 助教授 (80144393)
Project Period (FY) 1996 – 1997
Project Status Completed (Fiscal Year 1997)
Budget Amount *help
¥4,200,000 (Direct Cost: ¥4,200,000)
Fiscal Year 1997: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1996: ¥3,600,000 (Direct Cost: ¥3,600,000)
Keywordsgranular flow / particle collision / momentum transport / pyroclastic flow / nue ardente / fluidization / snow avalanche / snow ball / 衝突 / 熱風
Research Abstract

This research aims to present the unified theory of the flow of both the pyroclastic flow and the snow avalanche and to make possible to numerically simulate the actual phenomena.
First, the constitutive equations for the granular flow which take the inelastic collision, the kinetic momentum transport and static skeleton stress into account are deduced. Then, those equations are extended to a resistance to flow formula to explain the characteristic behaviors of the experimentally obtained laminar, laminar/dispersive and dispersive type flows.
This theory is applied to the Merapi type pyroclastic flow that occurred at the Fugendake, Unzen volcano. The processes of breaking the fallen lava dome into fragment and the flow of those pyroclastic material are satisfactory explained. Quantitative mechanism of formation, flow behaviors and the stoppage of the main basal fluidized layr and the nue 'ardent' part upon the basal layr which are the characteristic structure of the pyroclastic flow are made clear. A numerical simulation model based on the theory can explain the actual limits of flow as well as the distribution of the thickness of deposit within the area.
Processes of snow ball formation and the effects of snow balls to the characteristics of the flow are quantitatively explained by the granular flow theory. Moreover, the effect of the snow temperature to the formation of snow balls and the process of erosion and deposition are taken into account in the numerical simulation model. The model is applied to the 1986 Maseguchi snow avalanche (powder snow avalanche) and the 1992 Hakubadake avalanche (we snow avalanche) and the reporductions of both two phenomena are very good.

Report

(3 results)
  • 1997 Annual Research Report   Final Research Report Summary
  • 1996 Annual Research Report
  • Research Products

    (9 results)

All Other

All Publications (9 results)

  • [Publications] 高橋 保・辻本 浩史: "斜面上の粒状体流れの流動機構" 土木学会論文集. No.565/II-39. 57-71 (1997)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] 高橋 保 他: "火砕流の流動・堆積シミュレーション" 砂防学会誌. 50巻2号. 20-25 (1997)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] 高橋 保・辻本 浩史: "雪崩の流動機構に関する研究" 京都大学防災研究所年報. 40号B-2. 409-424 (1997)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Takahashi, T.and Tsujimoto, H.: "Mechanics of granular flow in inclined chute" Journal of Hydraulic, Coastal and Environmental Engineering, JSCE. No.565/II-39. 57-71 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Takahashi, T., Tsujimoto, H., Satofuka, Y.and Takeuchi, R.: "Numerical simulation of flow and deposition of a pyroclastic flow" Journal of JSECE. Vol.50, No.2. 20-25 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Takahashi, T.and Tsujimoto, H.: "Dynamics of the snow avalanche" Annuals, Disaster Prevention Research Institute, Kyoto Univ.No.40B-2. 409-424 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] 高橋 保・辻本浩史: "斜面上の粒状体流れの流動機構" 土木学会論文集. No.565/II-39. 57-71 (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] 高橋 保 他: "火砕流の流動・堆積シミュレーション" 砂防学会誌. 50巻2号. 20-25 (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] 高橋 保・辻本浩史: "雪崩の流動機構に関する研究" 京都大学防災研究所年報. 40号B-2. 409-424 (1997)

    • Related Report
      1997 Annual Research Report

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Published: 1996-04-01   Modified: 2016-04-21  

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