Microfiber coating for drag reduction on a cylinder

Abstract

The reduction of drag on a blunt body is a topic of considerable interest. Understanding drag reduction on a cylinder provides a fundamental understanding of the drag reduction on general blunt bodies. Herein, a microfiber coating with a hair-like structure is examined as a passive drag reduction coating on a cylinder. The drag reduction performance of the microfiber coating is studied in both symmetric and asymmetric configurations under the subcritical flow regime It is found that the symmetrically coated cylinder shows twice the drag reduction as that in the asymmetric case. It is shown that the angular position of the microfiber coating has a considerable impact on the performance of the coating and determines whether there is an increase or decrease in drag. This trend is consistent for both the asymmetric and symmetric configurations. It is also found that the flow features downstream of the cylinder are impacted by the configuration of the coating. The dominant frequency of the symmetric configuration in the rear flow of the cylinder is higher than that of the asymmetric configuration. The location of the dominant frequency is also further downstream for the symmetric configuration as compared to the asymmetric configuration.