Study of Reynolds number effect on turbulent boundary layer near the separation

22nd Fluid Mechanics Conference

物理学;力学

Drózdz, A.^1 ; Elsner, W.^1

Czstochowa University of Technology, Faculty of Mechanical Engineering and Computer Science, Armii Krajowej 21, Czestochowa

42-200, Poland^1

关键词: Experimental analysis;    External conditions;    Incipient detachments;    Mean velocity profiles;    Nonequilibrium boundaries;    Reynolds number effect;    Turbulence activity;    Turbulent boundary layers;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/760/1/012003/pdf
DOI  :  10.1088/1742-6596/760/1/012003

学科分类：力学，机械学

来源: IOP

【 摘 要 】

The paper deals with the experimental analysis of strong decelerated turbulent boundary layer developed on a flat plate. The special design of the test section equipped with perforated, movable upper wall allow to generate on the bottom wall turbulent boundary layer, which is at the verge of separation. The objective of the work is to examine the effect of Reynolds number on non-equilibrium boundary layer. A momentum thickness Reynolds number at the inlet to a test section was in the range from 6300 to 10150 what was achieved by varying wind tunnel speed. The emphasis is on the analysis of the streamwise Reynolds stress and mean velocity profiles and on related scaling issues problem. It was found that for the same external conditions defined by the pressure gradient coefficient Cp the effect of Reynolds number close the wall is seen even for such a narrow range of Reynolds number. In particular, the shape factor revealed more flow resistance on separation with increase in Reynolds number. The difference where observed mainly at the beginning of incipient detachment, where there is a drop of turbulence activity near the wall while it reaches a maximum value in the outer region.