Drag reduction of a microfiber-coated cylinder: influence of microfiber density

The development of drag reduction method is important for improving energy efficiency in engineering applications. While active methods that require external energy have attracted considerable attention, this study focuses on passive methods that do not use external energy. Microfiber coatings, which form an array of hair-like microfibers and can be taped to the surface of an object, have been studied as a potential passive drag reduction method. In this work, microfiber-coated cylinders with varying microfiber densities were fabricated to investigate the effect of microfiber density on a drag of a cylinder in the subcritical flow regime. The drag of microfiber-coated cylinder was measured and compared with that of a smooth cylinder (baseline). Results show that the microfiber-coated cylinder reduces the drag coefficient compared to the baseline, depending on the microfiber density. The current progress of this study and future directions will also be discussed.