Effects of Reynolds number and corner radius on twodimensional flow around dodecagonal cylinders
Abstract
Results are presented from an experimental study on viscous crossflow over dodecagonal cylinders with varying corner radii for several cylinderrelative wind orientations at Reynolds numbers from 0.1 to 1.5 times 10 to the 6th. These results include variation of both static crossflow lift and drag coefficients and Strouhal number with variation in Reynolds number, corner radius and windcylinder orientation and the variation of surface static pressure coefficients with angular position around the cylinders at selected values of Reynolds number, corner radius and windcylinder orientation. Test results indicate that for corner radii greater than 40.5% of the radius of the inscribed circular cylinder, the drag coefficient is approximately equal to or less than that of a circular cylinder at the same Reynolds number. Results also indicated supercritical static lift coefficients as large as 0.33 for cylinderrelative wind orientations of 5 deg and 10 deg and variations in Strouhal number of from 10 to 13% as the cylinder orientation is varied at a fixed Reynolds number. Strouhal numbers reached a maximum value of approximately 0.28 for cylinders with a corner radius of 40.5%. An analytic expression for the variation in force coefficient with variation in corner radius at a Reynolds number of 1,000,000 is also given.
 Publication:

American Institute of Aeronautics and Astronautics
 Pub Date:
 July 1980
 Bibcode:
 1980fpdy.confR....J
 Keywords:

 Corner Flow;
 Cross Flow;
 Cylindrical Bodies;
 Polygons;
 Reynolds Number;
 Two Dimensional Flow;
 Viscous Flow;
 Aerodynamic Drag;
 Aerodynamic Forces;
 Fluid Dynamics;
 Radii;
 Static Pressure;
 Strouhal Number;
 Fluid Mechanics and Heat Transfer