Experimental Investigation of Biofouled Ship Control Surface Performance

Abstract

Marine biofouling threatens ship safety by causing unexpected control surface performance. To explore these adverse biofouling effects, this paper presents the results of wind tunnel testing using a model-scale, low aspect ratio NACA 0018 control surface. Simulated calcareous biofouling was introduced as coarse-grit sandpaper, and, uniquely, roughness locations and sandpaper grits were varied to better understand any resulting degradation in hydrodynamic performance. Direct experimentation at high (turbulent) chord Reynolds number values suggests that leading-edge (LE) roughness with 36-grit sandpaper results in worst-case performance, with the control surface's average lift-to-drag ratio reduced by 63%. Additional findings are presented, and recommendations for future experimental work are also provided.