کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
293641 | 511161 | 2012 | 7 صفحه PDF | دانلود رایگان |

Three dimensional structures of unsteady flows behind a square prism with aspect ratio H/D=2.7 in a shallow boundary layer flow are investigated by two dimensional and three dimensional stereoscopic PIV techniques synchronizing with velocity measurement by a hot wire anemometer. According to the conditional PIV image sampling technique conducted by using the velocity signal measured outside the separated shear layer, it becomes clear that an arch-type vortex is formed behind the prism throughout a cycle of the Kármán vortex formation and shedding. As the vortex grows and moves downstream, the vortex line stretches in a stream-wise direction near the tip of the vortex which does not move and stays still just behind the prism throughout a cycle. According to POD analysis, the wake fluctuates very slowly with a period of approximately 6 times of that of the Kármán vortex shedding.
► Velocity vectors in wake behind a square prism were measured by 2D and 3D stereoscopic PIV.
► Velocity vectors in the wake were conditionally sampled synchronizing with Karman vortex shedding.
► An arch type vortex was observed throughout a cycle of Karman vortex formation.
Journal: Journal of Wind Engineering and Industrial Aerodynamics - Volumes 104–106, May–July 2012, Pages 196–202