Experimental Study on the Friction Drag Reduction of Hydrogel Paint in a Boundary Layer on Flat Plate

The drag reduction effect of hydrogel paint was experimentally investigated with the resistance test in a circular water tank. The hydrogel and non-hydrogel paints were coated on the 1.7-meters flat plate and the total drag force was measured with a one-component force meter up to the middle Reynolds number of 1.5 × 10⁶. The attachment of turbulence stimulator at the leading edge on the plate was also considered. The remarkable drag reduction was observed at the low Reynolds number of laminar-turbulent transition region and the hydrodynamic mechanism of its drag reduction was discussed.