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STUDY ON TURBULENCE STRUCTURE AND ACTIVE CONTROL OF A THREE-DIMENSIONAL SEPARATED FLOW

Research Project

Project/Area Number 05452148
Research Category

Grant-in-Aid for General Scientific Research (B)

Allocation TypeSingle-year Grants
Research Field Fluid engineering
Research InstitutionHOKKAIDO UNIVERSITY

Principal Investigator

KIYA Masaru  Hokkaido University, Fac.of Eng., Professor, 工学部, 教授 (50001160)

Co-Investigator(Kenkyū-buntansha) IDO Yasusi  Hokkaido University Fac.of Eng., Instructor, 工学部, 助手 (40221775)
MOCHIZUKI Osamu  Hokkaido University, Fac.of Eng., Associate Professor, 工学部, 助教授 (50157830)
Project Period (FY) 1993 – 1994
Project Status Completed (Fiscal Year 1994)
Budget Amount *help
¥6,200,000 (Direct Cost: ¥6,200,000)
Fiscal Year 1994: ¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 1993: ¥3,500,000 (Direct Cost: ¥3,500,000)
KeywordsTurbulent shear flow / Flow separation / Flow reattachment / Flow control / Active control / Sinusoidal disturbance / Separation bubble / Separated shear layr / はく離流れ / 乱流はく離泡 / 周期的攪乱 / 乱流 / 鈍頭物体
Research Abstract

A turbulent separation bubble formed by the boundary-layr separation from the leading edge of a blunt circular cylinder of semi-infinite length was forced by a single-frequency and two-frequency sinusoidal disturbances introduced uniformly along the separation edge. The disturbance was generated by a woofer inside the cylinder and introduced into the separated shear layr through a thin slot. Main results for the single-frequency forcing may be summarized as follows :
(1) The reattachment length attains a definite minimum at a particular forcing frequency if the r.m.s.forcing amplitude is less than 10% of the main-flow velocity. A flow model was proposed to successfully interpret this frequency (referred to as the most-effective frequency F) and the minimum reattachment length, which is a logarithmic function of the forcing amplitude.
(2) The separation bubble can be eliminated in a range of the forcing frequency for the forcing amplitudes greater than 14% of the main-flow velocity. This … More range of the forcing frequency tends to increase with increasing forcing amplitude. This result is useful in active control of flow separation on aerofoils and cascades of turbomachinery.
(3) The separation bubble is a self-excited flow maintained by a feedback loop : The disturbance produced by a large-scale vortex impinging on the surface in the reattachment region of the separation bubble propagates upstream as a pressure wave to be accepted at the sharp separation edge. The disturbance enhances the rolling-up of the separated shear layr.
(4) The structure of large-scale vortices in the separation bubble forced at the most effective frequency was obtained in terms of cross correlations of velocity fluctuations at two points separated in the circumferential direction and flow visualization by smoke wires and tuft probes.
Main results for the two-frequency forcing may be summarized as follows :
(5) The combination of the most effective frequency F and its higher harmonic 2F yields a minimum reattachment length at a phase difference of 0 and a maximum reattachment at another phase difference of pi. This result was successfully interpreted in terms of the subharmonic instability of the classical plane mixing layr.
(6) The two-frequency forcing yields approximately the same reduction of the reattachment length as the single-frequency forcing if the forcing amplitude is of the order of 10% of the main-flow velocity.
A discrete-vortex numerical simulation of the forced separation bubble reproduced the relation between the reattachment length and the forcing frequency, and more importantly useful pieces of information on a feedback control of the separation bubble. Less

Report

(3 results)
  • 1994 Annual Research Report   Final Research Report Summary
  • 1993 Annual Research Report
  • Research Products

    (20 results)

All Other

All Publications (20 results)

  • [Publications] M.KIYA: "Active Forcing of an Axisymmetric Leading-Edge Turbulent Separation Bubble" AIAA Paper. 93-3245. 1-11 (1993)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] M.KIYA: "The Forced Turbulent Separation Bubble" Proc.9th Symp.Turbulent Shear Flows. 1. 1.1.1-1.1.6 (1993)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] M.KIYA: "Structure of Turbulent Leading-Edge Separation Bubble of a Blunt Circular Cylinder and Its Response to Sinusoidal Disturbance" J.Wind Eng.& Indust.Aerodyn.49. 227-236 (1993)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] 清水昌幸: "バイモーダル攪乱による鈍頭円柱前縁はく離泡の制御" 日本機械学会論文集. 60. 432-437 (1994)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] 木谷 勝: "剥離流れの能動制御" ターボ機械. 22. 262-268 (1994)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] M.KIYA: "Forced Separation Bubble:Separated Shear Layer Interacting with Solid Surface" Proc.1st Int.Conf.on Flow Interaction. 200-203 (1994)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] M.Kiya, M.Shimizu, O.Mochizuki, Y.Ido and H.Tezuka: "Active Forcing of an Axisymmetric Leading-Edge Turbulent Separation Bubble" AIAA Paper. 93-3245. 1-11 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] M.Kiya, M.Shimizu, O.Mochizuki and Y.Ido: "The Forced Turbulent Separation Bubble" Proceedings of Ninth Symposium on Turbulent Shear Flows. Vol.1. 1.1.1-1.1.6 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] M.Kiya, O.Mochizuki, Y.Ido and H.Kosaku: "Structure of Turbulent Leading-Edge Separation Bubble of a Blunt Circular Cylinder ant its Response to Sinusoidal Disturbances" Journal of Wind Engineering and Industrial Aerodynamics. Vol.49. 227-236 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] M.Shimizu, M.Kiya, O.Mochizuki and Y.Ido: "Control of a Leading-Edge Separation Bubble by Bimodal Disturbances" Transactions of the JSME,Ser.B. Vol.60. 432-437 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] M.Kiya: "Active Control of Separated Flows" Turbomachinery. Vol.22. 262-269 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] M.Kiya, M.Shimizu, O.Mochizuki and Y.Ido: "Forced Separation Bubble : Separated Shear Layr Interacting with Solid Surface" Proceedings of First International Symposium on Flow Interaction. 200-203 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] 清水、昌幸: "バイモーダル攪乱による鈍頭円柱前縁はく離泡の制御" 日本機械学会論文集. 60. 432-437 (1994)

    • Related Report
      1994 Annual Research Report
  • [Publications] 木谷 勝: "剥離流れの能動制御" ターボ機械. 22. 262-268 (1994)

    • Related Report
      1994 Annual Research Report
  • [Publications] M.KIYA: "Forced Separation Bubble:Separated Shear Layer Interacting with Solid Surface" Proc.1ST Int.Couf.on Flow Iuteraction. 200-203 (1994)

    • Related Report
      1994 Annual Research Report
  • [Publications] M.KIYA,M.SHIMIZU,O.MOCHIZUKI,Y.IDO: "Active Forcing of an Axisymmetric Leading-Edge Turbulent Separation Bubble" AIAA Paper. 93-3245. 1-11 (1993)

    • Related Report
      1993 Annual Research Report
  • [Publications] M.KIYA,M.SHIMIZU,O.MOCHIZUKI,Y.IDO: "The Forced Turbulent Separation Bubble" Proc.9th Turbulent Shear Flows. 1. 1.1.1-1.1.6 (1993)

    • Related Report
      1993 Annual Research Report
  • [Publications] M.KIYA,O.MOCHIZUKI,Y.IDO,H.KOSAKU: "Structure of Turbulent Leading-Edge Separation Bubble of a Blunt Circular Cylinder and Its Response to Sinusoidal Disturbances" J.Wind Eng. & Indust.Aerodyn.49. 227-236 (1993)

    • Related Report
      1993 Annual Research Report
  • [Publications] 清水昌幸,木谷勝,望月修,井門康司: "バイモーダル攪乱による鈍頭円柱前縁はく離泡の制御" 日本機械学会論文集. 60. 82-87 (1994)

    • Related Report
      1993 Annual Research Report
  • [Publications] 井上良紀,木谷勝: "乱れと波の非線形現象" 朝倉書店, 195 (1993)

    • Related Report
      1993 Annual Research Report

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Published: 1993-04-01   Modified: 2016-04-21  

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