Experimental investigation on the aerodynamic behavior of square cylinders with rounded corners

Abstract The influence of corner shaping on the aerodynamic behavior of square cylinders is studied through wind tunnel tests. Beside the sharp-edge corner condition considered as a benchmark, two different rounded-corner radii (r/b=1/15 and 2/15) are studied. Global forces and surface pressure are simultaneously measured in the Reynolds number range between 1.7×104 and 2.3×105. The measurements are extended to angles of incidence between 0° and 45°, but the analysis and the discussion presented herein is focused on the low angle of incidence range. It is found that the critical angle of incidence, corresponding to the flow reattachment on the lateral face exposed to the flow, decreases as r/b increases and that an intermittent flow condition exists. In the case of turbulent incoming flow, two different aerodynamic regimes governed by the Reynolds number have been recognized.

[1]  R. Huang,et al.  Effects of Flow Patterns on Aerodynamic Forces of a Square Cylinder at Incidence , 2011 .

[2]  S. Yen,et al.  Flow patterns and vortex shedding behavior behind a square cylinder , 2011 .

[3]  Gl Larose,et al.  Experiments on 2D rectangular prisms at high Reynolds numbers in a pressurised wind tunnel , 2008 .

[4]  S. Yen,et al.  Time-averaged topological flow patterns and their influence on vortex shedding of a square cylinder in crossflow at incidence , 2010 .

[5]  B. J. Vickery Fluctuating lift and drag on a long cylinder of square cross-section in a smooth and in a turbulent stream , 1966, Journal of Fluid Mechanics.

[6]  Noel K. Delany,et al.  Low-speed drag of cylinders of various shapes , 1953 .

[7]  T. Tamura,et al.  Numerical prediction of unsteady pressures on a square cylinder with various corner shapes , 1998 .

[8]  C. Norberg Flow around rectangular cylinders: Pressure forces and wake frequencies , 1993 .

[9]  B. Lee The effect of turbulence on the surface pressure field of a square prism , 1975, Journal of Fluid Mechanics.

[10]  T. Igarashi Characteristics of the Flow around a Square Prism , 1984 .

[11]  Günter Schewe,et al.  Reynolds-number-effects in flow around a rectangular cylinder with aspect ratio 1:5 , 2013 .

[12]  Yasuharu Nakamura,et al.  The effects of turbulence on the mean flow past two-dimensional rectangular cylinders , 1984, Journal of Fluid Mechanics.

[13]  Qiusheng Li,et al.  An experimental investigation of the effects of free-stream turbulence on streamwise surface pressures in separated and reattaching flows , 1995 .

[14]  Tetsuro Tamura,et al.  The effect of turbulence on aerodynamic forces on a square cylinder with various corner shapes , 1999 .

[15]  Y. Nakamura,et al.  Critical geometry of oscillating bluff bodies , 1989, Journal of Fluid Mechanics.

[16]  Yasuharu Nakamura,et al.  The effects of turbulence on a separated and reattaching flow , 1987, Journal of Fluid Mechanics.

[17]  A. Okajima Strouhal numbers of rectangular cylinders , 1982, Journal of Fluid Mechanics.

[18]  Kenny C. S Kwok,et al.  Effect of edge configuration on wind-induced response of tall buildings , 1988 .