Effects of Flow Patterns on Aerodynamic Forces of a Square Cylinder at Incidence
Open Access
- 31 August 2011
- journal article
- Published by Oxford University Press (OUP) in Journal of Mechanics
- Vol. 27 (3), 347-355
- https://doi.org/10.1017/jmech.2011.37
Abstract
The pressure distributions around a square cylinder in a crossflow were experimentally studied in a wind tunnel. The subject of study was conventional, but the results presented new findings. The experiments were performed by using a home-made linear pressure scanner. The ranges of Reynolds number and incidence angle were 2 × 104- 9.4 × 104and 0° - 45°, respectively. According to the topological flow patterns, the flows around the square cylinder at incidence showed three characteristic regimes: The subcritical, supercritical, and wedge flows. A critical incidence angle αcri= 15° separated the regimes of subcritical and supercritical modes. The results of current study provided information regarding the effects of the topological flow patterns on surface pressure distribution, drag, and lift characteristics. The pressure distributions, drag, and lift presented different characteristics in different characteristic flow regimes and had close correlations with the flows. At the critical incidence angle 15° which separated the subcritical and supercritical regimes, the surface-averaged pressure coefficient on each face displayed local extreme value—The drag coefficient attained a minimum of 1.6, the lateral force coefficient reached a maximum of 0.9. The appearance of the minimum drag at the critical incidence angle was attributed to the reduction of wake width which was induced by two surface flow phenomena: (1) reattachment of the separated boundary layer on the lateral surface facing windward at the critical incidence angle and (2) flow pattern change on the lateral surface facing leeward.Keywords
This publication has 21 references indexed in Scilit:
- Time-averaged topological flow patterns and their influence on vortex shedding of a square cylinder in crossflow at incidenceJournal of Fluids and Structures, 2010
- The effect of turbulence on aerodynamic forces on a square cylinder with various corner shapesJournal of Wind Engineering and Industrial Aerodynamics, 1999
- A laser-Doppler velocimetry study of ensemble-averaged characteristics of the turbulent near wake of a square cylinderJournal of Fluid Mechanics, 1995
- Flow around rectangular cylinders: Pressure forces and wake frequenciesJournal of Wind Engineering and Industrial Aerodynamics, 1993
- Characteristics of the Flow around a Square PrismBulletin of JSME, 1984
- Strouhal numbers of rectangular cylindersJournal of Fluid Mechanics, 1982
- Influence of end plates and free ends on the shedding frequency of circular cylindersJournal of Fluid Mechanics, 1982
- The effects of tunnel blockage and aspect ratio on the mean flow past a circular cylinder with Reynolds numbers between 10 4 and 10 5Journal of Fluid Mechanics, 1982
- The effect of turbulence on the surface pressure field of a square prismJournal of Fluid Mechanics, 1975
- Fluctuating lift and drag on a long cylinder of square cross-section in a smooth and in a turbulent streamJournal of Fluid Mechanics, 1966