000181008 001__ 181008
000181008 005__ 20180317095307.0
000181008 0247_ $$2doi$$a10.1016/j.jfluidstructs.2011.12.003
000181008 022__ $$a0889-9746
000181008 02470 $$2ISI$$a000306883900008
000181008 037__ $$aARTICLE
000181008 245__ $$aHow oblique trailing edge of a hydrofoil reduces the vortex-induced vibration
000181008 269__ $$a2012
000181008 260__ $$bElsevier$$c2012
000181008 336__ $$aJournal Articles
000181008 500__ $$aHydrodyna Hydronet
000181008 520__ $$aThe effect of hydrofoil trailing edge shape on the wake dynamic and flow induced vibration is investigated at high Reynolds number, Re = 0.5 x 10(6)-2.9 x 10(6). Two NACA 0009 hydrofoils with blunt and oblique trailing edges are tested. The velocity field is surveyed with the help of Laser Doppler Velocimetry (LDV), and Particle-Image-Velocimetry, (Ply). Proper-Orthogonal-Decomposition (POD) is used to extract coherent structures from PIV data. Besides, flow induced vibration measurements and highspeed visualization are also performed. A significant reduction of vortex induced vibration is obtained with the oblique trailing edge, in accordance with former reports. High speed videos clearly demonstrate that for both tested hydrofoils, the alternate vortices detach from upper and lower corners of the trailing edge. Due to the oblique truncation, the lower detachment location is shifted upstream with respect to the upper one. Therefore, as the upper vortex rolls up, it coincides with the passage of the lower vortex, leading to their collision. This strong interaction leads to a redistribution of the vorticity, which no more concentrates within the core of Karman vortices. The analysis of the phase locked average of velocity profiles reveals that the oblique truncation leads to a thickening of the core of upper and lower vortices as well as a disorganization of the alternate shedding in the near wake, recovers downstream. We strongly believe that the collision between upper and lower vortices and the resulting vorticity redistribution is the main reason of the vibration reduction obtained with oblique trailing edge. This result paves the way for further optimization of the trailing edge shape. (C) 2011 Elsevier Ltd. All rights reserved.
000181008 6531_ $$aVortex shedding
000181008 6531_ $$aWake
000181008 6531_ $$aTrailing edge
000181008 6531_ $$aFlow-induced vibration
000181008 6531_ $$aFluid-structure interaction
000181008 6531_ $$aBluff-Body
000181008 6531_ $$aFlow
000181008 6531_ $$aHydrodyna
000181008 6531_ $$aHydronet
000181008 700__ $$0243099$$aZobeiri, A.$$g166861
000181008 700__ $$aAusoni, P.
000181008 700__ $$0241012$$aAvellan, F.$$g104417
000181008 700__ $$0240473$$aFarhat, M.$$g123870
000181008 773__ $$j32$$q78-89$$tJournal Of Fluids And Structures
000181008 8564_ $$s1558758$$uhttps://infoscience.epfl.ch/record/181008/files/JFS_Zobeiri_2012.pdf$$yPublisher's version$$zPublisher's version
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000181008 937__ $$aEPFL-ARTICLE-181008
000181008 973__ $$aEPFL$$rREVIEWED$$sPUBLISHED
000181008 980__ $$aARTICLE