Near wake structure behind a 3D square prism with the aspect ratio of 2.7 in a shallow boundary layer flow

Autor:	Yasuo Okuda, Masamiki Ohashi, Hiromasa Kawai
Rok vydání:	2012
Předmět:	Physics Renewable Energy Sustainability and the Environment business.industry Mechanical Engineering Geometry Wake Starting vortex Kármán vortex street Vortex ring Vortex Physics::Fluid Dynamics Boundary layer Optics Anemometer Prism business Civil and Structural Engineering
Zdroj:	Journal of Wind Engineering and Industrial Aerodynamics. :196-202
ISSN:	0167-6105
DOI:	10.1016/j.jweia.2012.04.019
Popis:	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 Karman 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 Karman vortex shedding.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::f0318871be0dadf29afa8d24cf5c0f64 https://doi.org/10.1016/j.jweia.2012.04.019 Zobrazit plný text záznamu Full Text from ScienceDirect