Slotted, natural-laminar-flow airfoil mounted vertically in the NASA Ames Transonic Wind Tunnel for testing. Photo by J. Coder
UNIVERSITY PARK, Pa. – In 2021, the Federal Aviation Administration (FAA) published a report highlighting the United States’ climate action plan to reduce carbon emissions from aviation, highlighting the need for more efficient transport aircraft. Penn State researchers, led by Jim Coder, Associate Professor of Aerospace Engineering, have concluded a major NASA-sponsored University Leadership Initiative effort titled the Advanced Aerodynamic Design Center for Ultra-Efficient Commercial Vehicles.
At the core of the project is a wing incorporating a slotted, natural-laminar-flow airfoil. On a typical airfoil, the airflow starts at the leading edge in a smooth ‘laminar’ flow over the wing, but at some point transitions to become turbulent, greatly increasing drag. A natural laminar flow airfoil is purposefully shaped to create a favorable pressure gradient across both the top and bottom of the wing, maintaining laminar flow for longer. Dr. Coder’s project studies further adding a slot in the airfoil to re-establish pressure at a critical point, creating extensive laminar flow along the airfoil, particularly in cruise configurations. The aft element can further be deflected for landing, like current-day landing flaps.
The airfoil was strategically developed to support NASA’s vision of a transonic, truss-based-wing aircraft. The truss structure removes the need for the wing alone to carry the entire weight of the aircraft, allowing it to be thinner. Dr. Coder, starting at his previous institute (the University of Tennessee at Knoxville) and then transitioning to join the faculty at Penn State in August 2022, designed the airfoil starting from theory, and expanding through a progressive series of computational analysis and wind tunnel tests. As a culmination, in 2022 Dr. Coder supervised a wind tunnel test in the NASA Ames Unitary Plan Wind Tunnel 11-ft transonic test section to validate the viability of SNLF for commercial transport applications.
Pressure contour over the airfoil as calculated computationally by solving the Reynolds-Averaged Navier Stokes (RANS) equations. Figure from “Computational Analysis of Boundary-Layer Instabilities on a Slotted, Natural-Laminar-Flow Airfoil,” M.S. Thesis by S.A. Gosin, Advised by J. Coder, Penn State, Fall 2023.
“Dr. Coder is notable for the degree to which his developments spanned the full scale of the airfoil development, from theory, through high-fidelity numerical simulations, and a series of wind tunnel tests,” notes Amy Pritchett, Professor and Head of Aerospace Engineering. “Rather than limiting his contributions to academic theory, he and his students have worked with NASA and industry partners to get his developments out into the industry. The increases in efficiency they have demonstrated are potentially a game changer for the industry.”
November 17, 2023 – ARP
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