MASSIVE advances in aerodynamicsAugust 30th, 2012 in Physics / General Physics
An image of the turbulent boundary layer. The velocity field of the turbulent boudary area. The turbulent flow exhibits a variety of arch- and cane-like vortex structures that evolve in time and space.
Engineers are closer to understanding, and therefore manipulating, invisible aerodynamic drag forces, that cause an estimated 50 per cent of transportation fuel to be lost before we can use it.
Director of Monash University's Laboratory for Turbulence Research in Aerospace and Combustion (LTRAC) Professor Julio Soria, said the technology to visualise these forces, which by causing drag or wind resistance, waste energy, was now available. Understanding and controlling these forces could lead to significant financial and environmental savings.
"We are trying to understand the turbulent boundary layer - the region right next to objects' surfaces that causes drag on aeroplanes, ships, trains, trucks - all vehicles, as well as the resistance to flow of water, oil and gas in pipes" Professor Soria said.
The LTRAC team is working on ways to manipulate this layer to control and reduce drag and increase aerodynamic efficiency.
"Based on Airbus estimates, even a 10 per cent reduction of this drag would result in a fuel savings corresponding to about 25 per cent of the operational cost," Professor Soria said.
The mechanics of turbulence of the boundary layer have remained a mystery because the structure of the boundary layer changes dramatically and unpredictably depending on the size of the object, its orientation and its speed. Further, it is almost impossible to effectively measure and analyse the conditions on a large object like the wing of an aircraft in motion.
Despite the challenges, Professor Soria and his team are making progress by taking advantage of two super computer facilities - the Multi-modal Australian ScienceS Imaging and Visualisation Environment (MASSIVE) at Monash and the National Computational Infrastructure in Canberra.
"We couldn't do these very large computations and visualisations without MASSIVE. To load and visualise this much data you need a supercomputer," Professor Soria said.
"Now we have better technology, we're seeing phenomena that we couldn't see before, and so didn't account for. As we delve deeper into the structure of the turbulent boundary layer, we find effects that we didn't even consider."
Professor Soria said the turbulent flows the team is visualising are unpredictable, but not random. They can see patterns and can observe the lifespan of clearly identifiable coherent structures in what seems to the naked eye to be a random flow.
"Once we understand this, we can design surface control strategies that manipulate the turbulent boundary layer to minimise drag which will result in more efficient vehicles, and less energy losses in the transport of liquids and gas in pipes. This will also reduce the amount of CO2 we produce, and the pain in our hip pockets."
Provided by Monash University
"MASSIVE advances in aerodynamics." August 30th, 2012. http://phys.org/news/2012-08-massive-advances-aerodynamics.html