Researchers Investigate Ring Wings
Abhinav Rao
Issue date: 11/11/09 Section: News
Using advanced computational techniques, researchers in aerospace engineering are analyzing the development of vortices on a ring-shaped airfoil and its applicability to a new breed of aircraft called micro-UAVs (micro Unmanned Aerial Vehicles). The curling of flow causes wingtip vortices over wingtips in a conventional finite lifting wing. However, the ring wing does not have definable wingtips and presents interesting theoretical possibilities and empirical results. This study was conducted and published by Kyle Wright, an undergraduate student in aerospace engineering, and Dr. Shigeo Hayashibara, professor of aerospace engineering.
Structurally, the ring wing that Wright is working with is a circular wing with non-lifting or symmetric airfoils at the sides transitioning to lifting airfoils at the top and bottom. The study showed that even in the extreme case in which the wing has no definable wingtips, vortices are still created as a consequence of generating lift. The aerodynamics of the ring wing are being analyzed using techniques of computational fluid dynamics, CFD, in which computer software is used to model the flow field.
"My research focuses on numerical analysis and seeing how the results compare with experiments. I am also working to accurately model the manner in which trailing vortices develop," said Wright. "The hypothesis was that the ring wing would show the formation of four separate vortices around the ring wing at the areas of transition from lifting to non-lifting surfaces. However, the computational results revealed the development of two main vortices in the wake of the ring wing"
To perform the analysis, Wright created meshes in which properties of the flow field are calculated numerically. The solutions in the finite volumes, when put together, revealed the characteristics of the entire flow domain. Students from the experimental aerodynamics class conducted tests at ERAU's two-foot by two-foot wind tunnel and have obtained experimental data for various ring wing designs. In addition, Wright compared the computed results with experimental data obtained by Dr. Lance Traub, professor of aerospace engineering.
While the research showed the presence of vortices and induced drag, the annular ring was also shown to have favorable stall characteristics. Today, many manufacturers are incorporating these airfoils into micro-UAVs.
In future analysis, Wright will make the CFD meshes finer to obtain a more in-depth picture of the development of vortices on the annular ring. He also hopes to present his research at the Applied Aerodynamics Conference.
Support for the research was provided by the NASA space grant.
Structurally, the ring wing that Wright is working with is a circular wing with non-lifting or symmetric airfoils at the sides transitioning to lifting airfoils at the top and bottom. The study showed that even in the extreme case in which the wing has no definable wingtips, vortices are still created as a consequence of generating lift. The aerodynamics of the ring wing are being analyzed using techniques of computational fluid dynamics, CFD, in which computer software is used to model the flow field.
"My research focuses on numerical analysis and seeing how the results compare with experiments. I am also working to accurately model the manner in which trailing vortices develop," said Wright. "The hypothesis was that the ring wing would show the formation of four separate vortices around the ring wing at the areas of transition from lifting to non-lifting surfaces. However, the computational results revealed the development of two main vortices in the wake of the ring wing"
To perform the analysis, Wright created meshes in which properties of the flow field are calculated numerically. The solutions in the finite volumes, when put together, revealed the characteristics of the entire flow domain. Students from the experimental aerodynamics class conducted tests at ERAU's two-foot by two-foot wind tunnel and have obtained experimental data for various ring wing designs. In addition, Wright compared the computed results with experimental data obtained by Dr. Lance Traub, professor of aerospace engineering.
While the research showed the presence of vortices and induced drag, the annular ring was also shown to have favorable stall characteristics. Today, many manufacturers are incorporating these airfoils into micro-UAVs.
In future analysis, Wright will make the CFD meshes finer to obtain a more in-depth picture of the development of vortices on the annular ring. He also hopes to present his research at the Applied Aerodynamics Conference.
Support for the research was provided by the NASA space grant.
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