Using corner chamfers to reduce the drag of flat-sided columns

Abstract

A comprehensive study of the drag forces acting on flat-sided columns is presented. The study considers a range of plane-sided column sections, from a sharp-cornered square section to varying degrees of corner chamfering and a full octagonal section. All chamfering was found to reduce the drag compared with the sharp-cornered case. It was also found there is a slight decrease in the drag coefficient as the Reynolds number of the fluid increases. For all cases except the octagonal section, drag increases significantly with increasing angle of attack. For the octagonal section, the drag coefficient increases then decreases as the angle of attack changes. The results agree with corresponding cases in the literature. The results are presented in a sequence of tables that allow users to estimate drag coefficients for any of the cases presented in the paper. As such, the study can serve as an archival repository for drag coefficient information. Comparisons of flow patterns are made, particularly in the wake region. It was found that the wake region becomes smaller as the chamfer becomes larger. The findings are important for the prediction of dynamic loads on exposed flat-sided columns above and below water, such as bridge pylons and offshore platform legs.

Numerical Simulation and Deep Neural Network Revealed Drag Reduction of Microstructured Three-Dimensional Square Cylinders at High Reynolds Numbers

“…The authors found that this structure reduced drag and discussed the fluid dynamical mechanism. Tong et al (2015) used chamfered corners to reduce the drag of 2D square cylinders with a sharp-angled square and octagonal cross section. The authors found that the chamfered structure reduces drag force compared with sharp corners.…”

A Numerical Investigation of Turbulent Flow Over Single and Tandem Square Cylinders

“…Tong et al [21] presented a numerical study for the flow over the chamfered square cylinders at varying degrees of chamfer and incident angles. It was concluded that chamfering reduced the drag coefficient compared with the sharp-cornered case.…”

LES of convective heat transfer and incompressible fluid flow past a square cylinder

“…After the wake flow measurements [6][7][8][9][10][11], Lyn and Rodi [12] conducted some experiments on the flapping shear layer formed by flow separation from the forward corner of a SC, with the associated recirculation region on the sidewall, and they found that the recirculation is an important aspect of some flow properties. For drag forces acting on flatsided columns, the study encompassed by Tong et al [13] revealed all chamfering can reduce the drag compared with the sharp-cornered case.…”