Nature’s Aerodynamic Blueprints Inspire New Engineering Designs
Researchers from STFC’s Scientific Computing Department (SCD) and the University of Manchester are using the surface patterns found in Nature to find ways to reduce fuel consumption and increase aerodynamic efficiency for aircraft, ships and cars.
The Challenge
When air passes over an aircraft wing the flow is disturbed by surface friction, separating the flow and leaving a gap above the surface, which creates a drag on the wing.
This surface friction drag and flow separation, which are common phenomenon in air, road and water vehicles, have a large impact on fuel consumption, cruising range, endurance and aerodynamic performance.
To reduce the impact, fin-like structures called vortex generators are attached to the leading edge of the wing to create a swirling mass of air that can reduce the separation gap. These are widely used for aerodynamic applications but are relatively large and can disrupt the entire field of flow if not used properly.
"Sharks and birds are both well adapted to moving efficiently through fluid, be it water or air. If you examine shark skin or bird feathers under a microscope, they both share a common feature: small directional grooves invisible to the naked eye that are used to control the flow of fluid over the surface."
Dr Jian Fang, STFC Scientific Computing
The Approach
The research team, led by SCD’s Dr Jian Fang, used high-fidelity computational simulations to study the airflow process and explore innovative ways to improve aerodynamic efficiency and reduce fuel consumption.
Inspired by the natural streamlined efficiency of birds and fish as they move through air and water, the team investigated the micro-scale pattern of ridges and grooves on bird feathers and shark skin. These tiny directional grooves, invisible to the naked eye, control the flow of fluids over their surface.
Dr Fang and his colleagues set about mimicking these groove patterns by implementing a technique which they called ‘convergent divergent riblets’ (or CDRs) as an alternative to the usual vortex generators.
Using the Hawk supercomputer at the High-Performance Computing Centre in Stuttgart, Germany, the team tested how the riblets would perform when air flows over them.
To do this, they adopted the direct numerical simulation approach to explore the details of the vortices induced by CDRs, using the ASTR code developed at SCD.
