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ISSN Online: 2379-1748
8th Thermal and Fluids Engineering Conference (TFEC)
EXPERIMENTAL INVESTIGATION OF DRAG REDUCTION OVER SUPERHYDROPHOBIC SURFACES IN AN OPEN CHANNEL FLOW
Abstract
Using commercial SH coating, this study investigates drag reduction (DR) over three fabricated superhydrophobic surfaces (SHSs). The SH surfaces were spray coated onto a test substrate of acrylic plate measuring an area of 0.5 m × 0.25 m. The static contact angles (SCA) were measured for each surface, with values as 145°, 147° and 155°. The experiments were conducted in an open channel flow facility, and the measurements were performed using a 2D- Laser Doppler Velocimetry (LDV) system. Seven measurement points were selected in streamwise flow. The experimental setup allows a flow of ReDh number 34200. The measurements were repeated twice for each surface. The results showed an average DR of 7%, 11% and 18%. The second trial showed slightly lower DR than the first trial, and point X7 showed drag enhancement in both trails, which refers to the surface topography change after the first measurements and the air layer thickness, as well as the flow's nature at the end of the test plate that caused by the turbulence and boundary layer separation at the channel gate.