Study on flow behind backward-facing step in a narrow channel

21st Fluid Mechanics Conference

物理学;力学

Uruba, V.^1

IT ASCR, Dolejskova 5, 182 00 Praha 8, Czech Republic^1

关键词: Backward facing step;    Channel widths;    Dynamical structure;    Flow reattachment;    Narrow channel;    Oscillation patterns;    Periodical structure;    Time-resolved piv;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/530/1/012024/pdf
DOI  :  10.1088/1742-6596/530/1/012024

学科分类：力学，机械学

来源: IOP

【 摘 要 】

Both statistics and dynamics of the flow-field behind a backward-facing step in a narrow channel is studied experimentally using time-resolved PIV technique. The channel width is 4 step heights, Reynolds number based on the step height was about 35 thousands. Secondary flow effect is detected clearly in the region behind the step resulting in strong 3D flow structure just behind the step. The low-frequency quasi-periodical structures appearing in the region behind the step and in the region of the flow reattachment close to the channel bottom are studied using the Oscillation Pattern Decomposition (OPD) technique. Strouhal numbers of those phenomena are very low, order of 0.01. Typical time-mean structures as well as dynamical structures are to be presented.