Reducing Shock Wave Strength on Airfoil Surfaces with Nanomaterial Coating at Supersonic Speed.

Shock wave formation in aircraft drastically retards the maneuverability of aircraft by increasing drag, destabilizing buffet, and diminishing engine efficiency. Conventional method of shock wave strength reduction by structural modifications are cumbersome and lack scalability and the repurposability is difficult to incorporate. The aim of this study was to investigate the effectiveness of nanomaterial coatings in reducing shock wave strength around airfoil surfaces. A nanocoating of graphene was applied to the surface of a TsAGI S-12 airfoil and the aerodynamic characteristics were evaluated. The flow visualization captured from the wind tunnel experiments at various Mach reveals 18% reduction in shock wave angle. The reduced shock wave angle and pressure coefficient confirmed that flow stability increased with increase in Mach, emphasizing that the technique is highly effective for supersonic speeds. Furthermore, to investigate the role of surface roughness, AFM measurements were performed, revealing that the surface roughness decreased from 10 to 2 nm. Notably, this decrease in surface roughness has a direct and vital influence on the reduction of shock wave strength. Specifically, the smoother surface offered by the nanocoating minimizes the irregular reflections that occur on rough surfaces, thereby dissipating the shock wave more effectively. The observed reduction in shock wave angle, surface drag, and static pressure has transpired as a consequence of the reduced surface roughness upon nanomaterial coating. Nanomaterial surface coating is a simple and highly effective method for shock wave strength reduction with scalability that can be readily employed in the aircraft industry. [ABSTRACT FROM AUTHOR]