Researchers in A&amp;A’s <a href="https://sites.uw.edu/cfmlab/" target="_blank">Computational Fluid Mechanics Lab</a> discovered a new law of fluid mechanics, a branch of physics, that will aid the future of aircraft design. The “Law of Incipient Separation” defines the maximum slope of an aircraft fuselage to avoid the separation of airflow that increases pressure-drag. Drag is the aerodynamic force that opposes forward motion.Getting the slope of the fuselage right will reduce the drag and create a more efficient aircraft to reduce fuel consumption. <a href="https://arc.aiaa.org/doi/abs/10.2514/1.J059611?journalCode=aiaaj" target="_blank">A new paper</a> written by Associate Professor Antonino Ferrante, Dawei Lu (M.S. 2019) and doctoral student Abhiram Aithal defines the parameters of this newly-discovered law.Aithal explains that getting as close as possible to flow separation is ideal. He says, “When the flow gets close to separation, the drag actually goes down, so the best scenario is to be as close to separation as possible without crossing the line because peak performance in control and efficiency is right before separation.” <div class="fr-img-space-wrap"><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1614123130418-picture-dept-article.jpg" style="width: 788px;" class="fr-fic fr-dib">A visualization of the relation of the slope of the jet’s afterbody to flow separation. Image credit: Cessna Citation X - N299CX - Gears Up - Wells Fargo Bank Na Trustee Corporate Jet - Waukegan Regional Airport by tncountryfan is licensed under CC BY 2.0.&nbsp;</div><h2>Patterns uncovered</h2>Says Ferrante, “I had an intuition that the law existed – nature follows laws that are just waiting to be discovered. Dawei and Abhiram worked out the simulations and data-analysis to prove it. We were able to discover a law that predicts the maximum slope a curved surface like the fuselage of an aircraft can have to avoid airflow separation based on the flow variables and few geometrical parameters to avoid flow separation.”Lu described the process of proving the law’s existence, saying that they first searched for an aircraft fuselage geometry from NASA in fluid mechanics literature. This geometry is an analytical model used to run computer simulations of aerodynamics. They first ran simulations with varied heights using this single geometry to find the slope value where flow gets close to separation. Next they ran hundreds of simulations for different geometries and flow parameters and filed a patent on these new geometries which will aid further research (U.S. Patent Application 63/027,041).“We had difficulty seeing the correlations of the data points at first,” Lu said, ”but after adjusting our methodology, the scattered data collapsed closer to one line on the plot - the maximum slope of flow separation.”“What surprised us most,” Lu continued, “was that the maximum slope of the aircraft body and not the maximum curvature or the shape of the curved surface dominates this phenomenon.”<h2>Further work</h2>The team is working on calculating the law’s more accurate coefficients by using more advanced numerical simulations. Ferrante says, “What is exciting is that we will be able to tell airplane designers that given a height and length of the aircraft and the general flight conditions you are expecting with this aircraft, that there is a defined maximum slope for the aircraft body that they should not exceed to keep the flow attached.” Thus far, the law has been determined for an incompressible flow, which covers flow aircraft such as small prop planes that travel much slower than the speed of sound. The team is working on including expanding the dataset to faster commercial airplanes.<h2>Reducing global emissions</h2>While the design of aircraft bodies may not seem to have changed much in the last several decades to outsiders, small changes bring large rewards. Slightly adjusting designs, such as the fuselage shape of an aircraft to get as close to flow separation as possible while keeping the flow attached could mean large savings in fuel and lower emissions for the aviation industry which contributes about 2.4 percent of global emission.Ferrante says, “Climate change is a huge motivator for me. If we can decrease airline fuel consumption by a few percent simply by adjusting aircraft design through the discovery of this new law, the statistic may seem small but on a global scale, that is a great accomplishment in reduction of fuel consumption and fossil fuel emissions.”Access the original paper:&nbsp;<a href="https://arc.aiaa.org/doi/full/10.2514/1.J059611" target="_blank">Law of Incipient Separation over Curved Ramps as Inferred by Reynolds-Averaged Navier–Stokes</a>

Photo credit: "toy jet; Citation Bravo" by Global Jet is licensed under CC BY 2.0

Researchers in A&A’s Computational Fluid Mechanics Lab discovered a new law of fluid mechanics, a branch of physics, that will aid the future of aircraft design.

New law of physics finds a sweet spot for aircraft efficiency

Creating a greener aerospace sector is key for the industry to bounce back from Covid-19 according to a new report released today.The second part of Protolabs’ Horizon Shift report – which involved aerospace business leaders from across Europe – reveals that more than three quarters of firms (77%) expect environmental credibility to become a key differentiator moving forward. Also, 72% indicate that new materials will be the driving force in lowering emissions and making flying cleaner.65% believe investment in innovation that reduces emissions should continue despite the pandemic, with 42% now transforming their supply chains as part of the innovation drive to cut down CO2 output.Senior executives from Composite Technology Center, Schiebel Group and Tecnam were among 80 senior leaders recently interviewed to understand how this critically important market was looking to recover from the far-reaching impact of Covid-19. The latest survey was conducted in June as a follow-up to an initial survey of 325 executives taken in February and March at the start of the pandemic. This latest report presents a unique insight into the sector, particularly in regard to what has changed as a result of the pandemic.In addition to environmental improvements, companies are also looking for Government support and stimulus packages to help them create new revenue streams, embed innovation in the supply chain and bring new products to market quickly.39% believe that there needs to be more immediate investment in infrastructure, whilst 33% are calling on more supportive fiscal policy, such as tax breaks or R&amp;D grants.“The two crises of climate change and the Covid-19 lockdowns are changing the face of the aerospace industry,” explained Bjoern Klaas, Vice President and Managing Director of Protolabs Europe, the world’s fastest digital manufacturer of custom prototypes and low-volume production parts.“New types of aircraft, business models and supply chains will emerge. Survival is not going to be about a fast transition, but about building up resilience for the long term and, part of that, is producing the next generation of aircraft: improved aerodynamics, lighter, more fuel-efficient and less polluting.”He continued: “Our latest Horizon Shift report brings this clearly into view. 77% of companies feel environmental performance will be a key differentiator, a 9% increase from when we asked the same question in our initial survey just before the lockdowns.“91% of business leaders admit that cutting CO2 is having some form of impact on how they run their companies and the good news for the European aerospace sector is that it appears they’ve decided to embrace the pressure by transforming supply chains and developing new technologies and materials.“Earlier this year, Airbus reconfirmed its commitment to decarbonisation and leading the development of a more sustainable global aerospace industry – this is a commitment that will filter through its supply chain.”The Horizon Shift report delves into challenges facing the supply chain and what operational improvements the sector is taking to overcome these.Top of the list of concerns for companies over the next two years was environmental compliance, followed by inflexibility/long supply chain delays (69%) and length of certification process (60%). Volatility in raw material costs and availability (57%) was also a key talking point.The research found that firms expect to move from using advanced manufacturing techniques in order to enhance productivity and output, to using them to create a more flexible product range (63%) and deliver parts/aircraft quicker (58%).3D printing’s transformation from a prototyping technology into a full production technology was also discussed in the Protolabs report. Through using the technology, companies talked of processing materials at a greater speed, with less waste, and even compressing multiple components into a single lighter 3D printed part.Bjoern concluded: “Companies that are experiencing financial pressures in the aftermath of Covid-19 are now focusing on quick wins and speed to market. One way to plan ahead is to create additional revenue streams, but this requires supply chain optimisation and increasing speed to market.“In the longer-term, our survey shows that they will look to hire talent, implement new technologies, use new materials and expand their manufacturing capabilities. They might see some unexpected positive outcomes from the crisis: flexibility from upgraded manufacturing supply chains and processes giving the ability to cater to consumer and social pressures with more environmentally friendly aircraft.”To download the second part of the Horizon Shift report, <a href="https://get.protolabs.co.uk/aerospace-chapter-two/?utm_source=wevolver&utm_medium=referral&utm_campaign=uk-aerospace-chap2-0920&utm_content=press-release-aerospace-chap2-0920" rel="noopener noreferrer" target="_blank">please click here</a>. If you would like further information, please visit <a href="http://www.protolabs.co.uk?utm_source=wevolver&utm_medium=referral&utm_campaign=uk-aerospace-chap2-0920&utm_content=press-release-aerospace-chap2-0920" rel="noopener noreferrer" target="_blank">www.protolabs.co.uk</a>

electric aircraft

ORGANIZATIONS. SHAPING THE INDUSTRY.

Latest Posts

New law of physics finds a sweet spot for aircraft efficiency

Aerospace companies still set to invest in green opportunities despite Covid-19 reveals new report