Study of Serrated Backwards Facing Steps in an Adverse Pressure Gradient via Computational Methods

A thin layer of tape that acts as a backwards facing step (BFS) is applied to wind turbine blades for protection from wind, erosion, debris, etc. However, the addition of the thin layer is known to add drag, which reduces the electrical power output of a turbine. A novel tape design with serrated edges instead of traditional BFS, termed Serrated Backwards Facing Step (sBFS) can provides the protection while mitigating the negative impact of the BFS formed from traditional films. In a previous wind tunnel study, it was shown that the sBFS were able to produce strong coherent structures in the far wake region as well as produce less drag than a traditional BFS. Utilizing a commercial computational fluid dynamics (CFD) package (Star-CCM+), the current study looks to study the sBFS in adverse pressure gradients. Along with comparison to the experimental data, the pressure gradient will be varied and new sBFS configurations examined with the goal of finding an optimal configuration for drag.