Suppression of Karman vortex formation behind 2-D bluff bodies

2015 Fiscal Year Final Research Report

• Project/Area Number: 25420846
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Aerospace engineering
• Research Institution: Tokyo Metropolitan University (2014-2015); Muroran Institute of Technology (2013)
• Principal Investigator: Takagi Shohei 首都大学東京, システムデザイン研究科, 教授 (10358658)
• Co-Investigator(Kenkyū-buntansha): ASAI MASAHITO 首都大学東京, システムデザイン研究科, 教授 (00117988) ; NORO SHUTA 仙台高等専門学校, 機械システム工学科, 助教 (30709192)
• Co-Investigator(Renkei-kenkyūsha): KONISHI YASUFUMI 東北大学, 流体科学研究所, 研究支援者 (20552540)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 二次元後流 / カルマン渦列 / 渦列抑制 / 全体不安定

Outline of Final Research Achievements

It is well known that since the regular-vortex street formed behind 2-D bluff bodies2-D airfoil model is associated with the so-called global instability of temporal type, a vortex passing frequency is very monochromatic. A wire rod with a diameter of one-fortieth of the airfoil chord was immersed at the suction side of the model at a distance of 75% chord transversally from the model edge, resulting in complete suppression of the vortex formation. In order to unravel the vortex-suppression mechanism, elaborate measurements of mean velocity profiles making use of a hot-wire anemometer were performed with and without a control wire. Comparison of two cases shows that insertion of the wire deflects local flow angle and results in reduction of attack angle of the model.
Along with this informative achievement, a flat plate in place of the wire was used to deflect the flow angle. Temporal growth rate and temporal attenuation rate associated with the global instability were measured.

Free Research Field

工学