TY - JOUR
T1 - Experimental study on laminar flow over two confined isothermal cylinders in tandem during mixed convection
AU - Salcedo, E.
AU - Treviño, C.
AU - Palacios-Morales, C.
AU - Zenit, R.
AU - Martínez-Suástegui, L.
N1 - Publisher Copyright:
© 2017 Elsevier Masson SAS
PY - 2017/5/1
Y1 - 2017/5/1
N2 - An experimental investigation of laminar aiding and opposing mixed convection is carried out using particle image velocimetry (PIV) to assess the thermal effects on the wake of two isothermal cylinders of equal diameter in tandem array placed horizontally and confined inside a vertical closed-loop downward rectangular water channel. The buoyancy effect on the flow distributions are revealed for flow conditions with Reynolds number based on cylinder diameter of Re = 100 and 200, blockage ratio of BR = D/H = 0.3, aspect ratio of AR = W/D = 5, pitch-to-diameter ratio of σ=L/D = 3, and values of the buoyancy parameter (Richardson number) in the range −1≤Ri≤ 3. In this work, the interference effects on the complex flow features are presented in the form of mean and instantaneous contours of velocity and vorticity. In addition, separation angles, wake structure, recirculation bubble lengths, time traces of velocity fluctuation, Strouhal number and vortex shedding modes of the two-cylinder system are obtained as a function of the Richardson number. In this arrangement, the results indicate that the effects of the Reynolds number are very pronounced, and that the vortex shedding patterns exhibit a strong dependence on Ri. We also show the modulation effect of the channel walls on the three-dimensional flow under varying thermal buoyancy, and the results reported herein demonstrate how the flow structure, wake behavior and vortex shedding pattern are entirely different from that behind a single circular cylinder under wall confinement and thermal effects.
AB - An experimental investigation of laminar aiding and opposing mixed convection is carried out using particle image velocimetry (PIV) to assess the thermal effects on the wake of two isothermal cylinders of equal diameter in tandem array placed horizontally and confined inside a vertical closed-loop downward rectangular water channel. The buoyancy effect on the flow distributions are revealed for flow conditions with Reynolds number based on cylinder diameter of Re = 100 and 200, blockage ratio of BR = D/H = 0.3, aspect ratio of AR = W/D = 5, pitch-to-diameter ratio of σ=L/D = 3, and values of the buoyancy parameter (Richardson number) in the range −1≤Ri≤ 3. In this work, the interference effects on the complex flow features are presented in the form of mean and instantaneous contours of velocity and vorticity. In addition, separation angles, wake structure, recirculation bubble lengths, time traces of velocity fluctuation, Strouhal number and vortex shedding modes of the two-cylinder system are obtained as a function of the Richardson number. In this arrangement, the results indicate that the effects of the Reynolds number are very pronounced, and that the vortex shedding patterns exhibit a strong dependence on Ri. We also show the modulation effect of the channel walls on the three-dimensional flow under varying thermal buoyancy, and the results reported herein demonstrate how the flow structure, wake behavior and vortex shedding pattern are entirely different from that behind a single circular cylinder under wall confinement and thermal effects.
KW - Blockage ratio
KW - Interference effects
KW - PIV
KW - Tandem cylinders
KW - Vortex shedding
KW - Wall effects
UR - http://www.scopus.com/inward/record.url?scp=85012284452&partnerID=8YFLogxK
U2 - 10.1016/j.ijthermalsci.2017.01.015
DO - 10.1016/j.ijthermalsci.2017.01.015
M3 - Artículo
SN - 1290-0729
VL - 115
SP - 176
EP - 196
JO - International Journal of Thermal Sciences
JF - International Journal of Thermal Sciences
ER -