Investigation of flow characteristics around a sphere placed in a boundary layer over a flat plate
Küçük Resim Yok
Tarih
2013
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
ELSEVIER SCIENCE INC
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
Flow characteristics around a sphere located over a smooth flat plate were experimentally investigated using dye visualization and PIV technique. The sphere was embedded in a turbulent boundary layer with a thickness of 63 mm which was larger than the sphere diameter of D = 42.5 mm. Instantaneous and time-averaged flow patterns in the wake region of the sphere were examined from the point of flow physics for different sphere locations in the range of 0 <= G/D <= 1.5 where G was the space between the bottom point of the sphere and the flat plate surface. Reynolds numbers with a range of 2500 <= Re <= 10000 based on the free-stream velocity while the velocity distributions over the plate surface are the developed turbulent boundary layer condition attained by using a tripwire. Distributions of velocity fluctuations, patterns of sectional streamlines, vorticity contours, velocity fields, turbulent kinetic energy and corresponding Reynolds stress correlations are obtained using PIV data. It was found that a jet-like flow stimulated the flow entrainment between the core and wake regions as a function of the sphere locations. The gap ratio has a strong influence on the flow structure of the wake-boundary layer interaction and the variation of the reattachment location of the separated flow from the plate surface. The time-averaged flow patterns yield asymmetric structures downstream of the sphere due to the effect of the boundary layer flow distribution. (C) 2012 Elsevier Inc. All rights reserved.
Açıklama
Anahtar Kelimeler
Boundary layer, Flow visualization, Reattachment, Sphere, PIV, Turbulence, Vorticity, Wake
Kaynak
EXPERIMENTAL THERMAL AND FLUID SCIENCE
WoS Q Değeri
Q1
Scopus Q Değeri
Q1
Cilt
44
