No abstract

Since the invention of the aircraft, there has been a need for better surface design to enhance performance. This thirst has driven many aerodynamicists to develop various types of aerofoils. Most researchers have strongly assumed that smooth surfaces would be more suitable for air transport vehicles. This ideology was shattered into pieces when biomimetics was introduced. Biomimetics emphasized the roughness of a surface instead of smoothness in a fluid flow regime. In this research, the most popular 0012 aerofoils of the National Advisory Committee for Aeronautics (NACA) are considered to improve them, with the help of a surface pattern derived from the biological environment. Original and biomimetic aerofoils were designed in three dimensions with the help of Solidworks software and analyzed in the computational flow domain using the commercial code ANSYS Fluent. The implemented biomimetic rough surface pattern upgraded the NACA 0012 aerofoil design in the transonic flow regime. Lift and viscous forces of the aerofoil improved up to 5.41% and 9.98%, respectively. This research has proved that a surface with a little roughness is better than a smooth surface.

Purpose Since the inception of aerospace engineering, reducing drag is of eternal importance. Over the years, researchers have been trying to improve the aerodynamics of National Advisory Committee for Aeronautics (NACA) aerofoils in many ways. It is proved that smooth-surfaced NACA 0012 aerofoil produces more drag in compressible flow. Recent research on shark-skin pattern warrants a feasible solution to many fluid-engineering problems. Several attempts were made by many researchers to implement the idea of shark skin in the form of coatings, texture and more. However, those ideas are at greater risk when it comes to wing maintenance. The purpose of this paper is to implement a relatively larger biomimetic pattern which would make way for easy maintenance of patterned wings with improved performance. Design/methodology/approach In this paper, two biomimetic aerofoils are designed by optimizing the surface pattern of shark skin and are tested at different angles of attack in the computational flow domain. Findings The results of the biomimetic aerofoils prove that viscous and total drag can be reduced up to 33.08% and 3.68%, respectively, at high subsonic speed when validated against a NACA 0012 aerofoil. With the ample effectiveness of patched shark-skin pattern, biomimetic aerofoil generates as high as 10.42% lift than NACA 0012. Originality/value In this study, a feasible shark-skin pattern is constructed for NACA 0012 in a transonic flow regime. Computational results achieved using the theoretical model agree with experimental data.

Butterfly valves are most commonly used in aerospace and mechanical industries to regulate fluid flow. Although butterfly valves are known for their low pressure drop functions, still instabilities occur when operating the valves from closed to open positions. Disturbances like the skin friction and turbulence kinetic energy of the disc greatly reduce the outlet velocity of the fluid. Although there are many techniques to address the disturbances, studies on the sharkskin pattern gained a spotlight in solving both aerodynamic and hydrodynamic problems in internal flows. In this computational work, the performance of the butterfly valve is improved with the help of the implemented biomimetic pattern on the surface. It was noted from the computational analysis that the skin friction coefficient, turbulence kinetic energy and outlet velocity of the butterfly valve could be enhanced by up to 83.24, 45.54 and 3.42%, respectively. The net mass flow rate of the pipe is also improved with the help of the biomimetic butterfly valve. Computational results were validated to ensure its steadiness. This computational research is proof of the concept ‘fluid flow over a surface with little roughness is better than a smooth surface’.

In the past two years, the pandemic situation has affected the aviation industry drastically. This situation starts to change, gradually, which is about to highly increase the international air travel around the world. Commercial air transport emission contributes a significant amount to global warming. Hence, in this research, to reduce the fuel consumption in commercial aircraft the aerodynamic surface of the wing is improved with the help of a hollow model in three dimensions. This biomimetic model named Raw Riblet was derived from a shark's skin texture.The cross-section of the wing was (NACA 0012) designed and the Raw Riblet model was implemented in two different ways, computationally, and formulated biomimetic aerofoil models such as BRR and LRR (0.455). All these aerofoil models were analysed in high-speed airflow, computationally, and the aerodynamic performance values were noted. All the computational results were validated, and the result analysis showed a promising decrease in viscous drag of up to 11%. Both biomimetic models performed well in disturbance reduction when compared to the NACA model. This improved aerodynamic surface with reduced drag would decrease the fuel consumption in aircraft. This computational model would help us to fight the war against global warming.