TY - JOUR
T1 - Robotic PTV study of the flow around automotive side-view mirror models
AU - Kim, Dong
AU - Kim, Mirae
AU - Saredi, Edoardo
AU - Scarano, Fulvio
AU - Kim, Kyung Chun
PY - 2020/11/1
Y1 - 2020/11/1
N2 - The flow around three simplified models of side-view mirrors for automobiles is experimentally investigated by means of Robotic particle tracking velocimetry (PTV). The measurements are performed coupling a coaxial volumetric velocimeter with time-resolved three-dimensional (4D) Lagrangian Particle Tracking (LPT) data analyzed with the Shake-The-Box (STB) algorithm. Helium-filled soap bubbles were used as tracers in the wind tunnel experiment to achieve the measurement volume needed for characterizing the flow structures around and behind the models of automobile side-view mirrors. The aspect ratio of all the models is kept constant to H/W = 2. The effect of a slant angle at the front and the reduction of cross section at the model root are specifically investigated respectively using model 2 and model 3. In model 1 which represents generic geometry having semi-cylinder-spherical shape, the extension of the recirculation zone shrank in the z direction due to the free-end effect. When the flow is developing downstream, a vortex pair inclines towards the ground plane due to the downwash effect. This streamwise vortex shows a dipole distribution. In model 2 the trailing vortex does not fall toward downstream because a base vortex with opposite sign formed under the trailing vortex. This prevents the downwash flow from reaching the ground plane. In model 3, a streamwise vortex is generated from a strong upwash flow, which generates a short trailing vortex up to x/H = 1. This occurs because the vortex that was formed from the top and side end is suppressed and destroyed. The leg of the reverse U-shape structure of model 1 is almost perpendicular to the ground plane. However, in models 2 and 3, vortex shedding near the bottom is delayed, and an arch vortex is slightly slanted toward the model body.
AB - The flow around three simplified models of side-view mirrors for automobiles is experimentally investigated by means of Robotic particle tracking velocimetry (PTV). The measurements are performed coupling a coaxial volumetric velocimeter with time-resolved three-dimensional (4D) Lagrangian Particle Tracking (LPT) data analyzed with the Shake-The-Box (STB) algorithm. Helium-filled soap bubbles were used as tracers in the wind tunnel experiment to achieve the measurement volume needed for characterizing the flow structures around and behind the models of automobile side-view mirrors. The aspect ratio of all the models is kept constant to H/W = 2. The effect of a slant angle at the front and the reduction of cross section at the model root are specifically investigated respectively using model 2 and model 3. In model 1 which represents generic geometry having semi-cylinder-spherical shape, the extension of the recirculation zone shrank in the z direction due to the free-end effect. When the flow is developing downstream, a vortex pair inclines towards the ground plane due to the downwash effect. This streamwise vortex shows a dipole distribution. In model 2 the trailing vortex does not fall toward downstream because a base vortex with opposite sign formed under the trailing vortex. This prevents the downwash flow from reaching the ground plane. In model 3, a streamwise vortex is generated from a strong upwash flow, which generates a short trailing vortex up to x/H = 1. This occurs because the vortex that was formed from the top and side end is suppressed and destroyed. The leg of the reverse U-shape structure of model 1 is almost perpendicular to the ground plane. However, in models 2 and 3, vortex shedding near the bottom is delayed, and an arch vortex is slightly slanted toward the model body.
KW - Automobile
KW - Coaxial volumetric velocimetry
KW - Juncture flow
KW - Lagrangian particle tracking
KW - Robotic PTV
KW - Shake-the-box algorithm
KW - Side view mirror
KW - Vortex structures
UR - http://www.scopus.com/inward/record.url?scp=85086859091&partnerID=8YFLogxK
U2 - 10.1016/j.expthermflusci.2020.110202
DO - 10.1016/j.expthermflusci.2020.110202
M3 - Article
AN - SCOPUS:85086859091
SN - 0894-1777
VL - 119
JO - Experimental Thermal and Fluid Science
JF - Experimental Thermal and Fluid Science
M1 - 110202
ER -