Abstract
There are no studies specifically aimed at characterizing and quantifying drag forces on finite cylinder arrays in the mixing layer of compound channel flows. Addressing this research gap, the current study is aimed at characterizing experimentally drag forces and drag coefficients on a square-cylinder array placed near the main-channel/floodplain interface, where a mixing layer develops. Testing conditions comprise two values of relative submergence of the floodplain and similar ranges of Froude and bulk Reynolds numbers. Time-averaged hydrodynamic drag forces are calculated from an integral analysis: the Reynolds-averaged integral momentum (RAIM) conservation equations are applied to a control volume to compute the drag force, with all other terms in the RAIM equations directly estimated from velocity or depth measurements. This investigation revealed that, for both tested conditions, the values of the array-averaged drag coefficient are smaller than those of cylinders in tandem or side by side. It is argued that momentum exchanges between the flow in the main channel and the flow in front of the array contributes to reduce the pressure difference on cylinders closer to the interface. The observed drag reduction does not scale with the normalized shear rate or the relative submersion. It is proposed that the value of the drag coefficient is inversely proportional to a Reynolds number based on the velocity difference between the main-channel and the array and on cylinder spacing.
Funder
Fundação para a Ciência e Tecnologia
European Union
Subject
Water Science and Technology,Aquatic Science,Geography, Planning and Development,Biochemistry
Reference44 articles.
1. Where do floodplains begin? The role of total stream power and longitudinal profile form on floodplain initiation processes
2. General classification handbook for floodplain vegetation in large river systems
3. Pressure and Frictional Resistance of a Cylinder at Reynolds Numbers 5000 to 40,000;Schiller,1933
4. On the Drag and Shedding Frequency of Two-Dimensional Bluff Bodies;Roshko,1954
5. Flow around Circular Cylinders. Volume 1: Fundamentals;Zdravkovich,1997
Cited by
1 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献