Design, Fabrication, and Performance Evaluation of Drag Reductive Functional Surfaces with Streamwise Triangular Riblets

Drag reductive functional surfaces can reduce the environmental impact and operational costs, and improve the performance of equipment in various industries. These motivations lead to the increasing demand for scientific understanding of the mechanism behind drag reduction and engineering developing the manufacturing, modeling, and testing of the surfaces. CFD simulations were used to analyze the turbulent flow surrounding the riblets (protrusions defining the surface) using unique variables. Pressure differential experiments were used for validation of the drag reduction results. It was shown both computationally and experimentally that a maximum of roughly 10% drag reduction is possible using streamwise triangular riblets and the non-dimensional riblet spacing that this occurs at is proportional to the included angle. Additionally, groundwork for a new experimental Taylor-Couette system was done including design, fabrication, and testing. The groundwork for this experiment will successfully allow future studies to easily evaluate the drag reductive properties of various surfaces.