Turbulent Shear Flow Downstream of a Sphere with and Without an O-Ring Located Over a Plane Boundary
Yükleniyor...
Dosyalar
Tarih
2012
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
E D P SCIENCES
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Flow-structure interaction of separated shear flow from the sphere and a flat plate was investigated by using dye visualization and the particle image velocimetry technique. Later, a passive control method was applied with 2mm o-ring located on the sphere surface at 55 degrees from front stagnation point. The experiments were carried out in open water channel for Reynolds number value of Re=5000. Flow characteristics have been examined in terms of the 2-D instantaneous and time-averaged velocity vectors, patterns of vorticity, streamlines, rms of velocity fluctuations and Reynolds stress variations and discussed from the point of flow physics, vortex formation, lengths of large-scale Karman Vortex Streets and Kelvin-Helmholtz vortices depending on the sphere locations over the flat plate. It is demonstrated that the gap flow occurring between the sphere bottom point and the flat plate surface has very high scouring effect until h/d=0.25 and then unsymmetrical flow structure of the wake region keeps up to h/D=1.0 for smooth sphere. For the sphere with o-ring, the wake flow structure becomes symmetrical at smaller gap ratios and reattachment point on the flat plate surface occurs earlier. Moreover, o-ring on the sphere diminishes peak magnitudes of the flow characteristics and thus it is expected that the flow-induced forces will be lessened both on the sphere and flat plate surface. Vortex formation lengths and maximum value occurring points become closer locations to the rear surface of the sphere with o-ring.
Açıklama
Conference on Experimental Fluid Mechanics (EFM) -- NOV 22-25, 2011 -- Jicin, CZECH REPUBLIC
Anahtar Kelimeler
boundary layer, o-ring, sphere, PIV, passive control, turbulence, vorticity, wake
Kaynak
Efm11 - Experimental Fluid Mechanics 2011
WoS Q Değeri
N/A
Scopus Q Değeri
N/A
Cilt
25
Sayı
Künye
Özgören, M., Okbaz, A., Doğan, S., Şahin, B., Akıllı, H., (2012). Turbulent Shear Flow Downstream of a Sphere with and Without an O-Ring Located Over a Plane Boundary. Experimental Fluid Mechanics 2011, 25, 1-14. DOI: 10.1051/epjconf/20122501066
