G.A.Voropaev, A.V.Voskoboinick, V.A.Voskoboinick, S.A.Isaev Laminar flow visualization over oval dimple |
Applied hydromechanics, Vol. 11 (83) ¹ 4, (2009) |
| In this paper the results of experimental researches of forming of vortical flow are presented into an oval dimple, located on a flat surface, for the laminar regime of its flowing around of different visualization methods of stream. The optimum parameters of asymmetric oval dimple are certain from point of most heat-hydraulic efficiency and forming of steady vortical structures in its wake, namely length of cylindrical insertion is equal to the diameter of spherical segment and corner of location of dimple of 60o in relation to direction of the stream. During optimum configuration of dimple a steady large-scale coherent fusiform vortical structure is formed in it. A fusiform vortex, accomplishing oscillation, both joins in with the bottom of forage spherical part of the dimple or break up from it. At the break up a fusiform vortex takes a form of tornado-like vortex, focus of which is on a front to streamwise spherical side of the dimple, and a flow is periodically break up in a boundary layer behind forage spherical part of the dimple, forming a longitudinal coherent vortical structure. Most strongly the break up of vortical structures at a=60o is observed in middle cylindrical part of the oval dimple, that to stipulate appearance in near wake of this part of the dimple of maximal levels of shear stresses. |
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KEY WORDS: *** |
| TEXT LANGUAGE: Russian |