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Full-Text Articles in Engineering
Modeling And Simulation Research And Instruction At The U.S. Air Force Academy, Russell M. Cummings, Scott A. Morton, Keith Bergeron
Modeling And Simulation Research And Instruction At The U.S. Air Force Academy, Russell M. Cummings, Scott A. Morton, Keith Bergeron
Aerospace Engineering
Modeling and simulation has become a driving force within the engineering and science communities as the cost of, and time for, experimentation continues to rise. Some areas of study, such as chemistry and biology, may not even have the ability to fully evaluate certain processes experimentally, making modeling and simulation even more important. The situation has led many areas of research to the necessity of modeling and simulating various processes using computers. In addition, the rise in computational capabilities (the supercomputers of a decade ago are outmoded by the PC clusters of today), has led to a paradigm shift from …
High Resolution Turbulence Treatment Of F/A-18 Tail Buffet, Scott A. Morton, Russell M. Cummings, Denis B. Kholodar
High Resolution Turbulence Treatment Of F/A-18 Tail Buffet, Scott A. Morton, Russell M. Cummings, Denis B. Kholodar
Aerospace Engineering
Unsteady tail loads of the F/A-18 are computed using various turbulence models at an angle of attack consistent with buffet induced by leading-edge extension vortex breakdown. Comparison of these industry standard turbulence models with the Detached Eddy Simulation (DES) hybrid RANS-LES approach reveals the inadequacies of RANS methods and the ability of DES to reproduce the observed unsteadiness at these conditions. Computed vortex breakdown position and frequencies of the DES method are shown to be accurate by comparison to flight test and experimental results. Finally, comparison of the DES unsteady tail pressures with flight-test tail pressures reveal the ability of …
Airplane Design And The Biomechanics Of Flight – A More Completely Multi- Disciplinary Perspective, John H. Mcmasters, Russell M. Cummings
Airplane Design And The Biomechanics Of Flight – A More Completely Multi- Disciplinary Perspective, John H. Mcmasters, Russell M. Cummings
Aerospace Engineering
Aeronautics is usually presumed to have started as a formal engineering discipline somewhere in historical time between the mythological experiments of Daedalus and his ill-fated son, Icarus; and the dreams and schemes of Leonardo da Vinci during the Italian Renaissance. As reviewed in this paper, “aeronautics” has a far longer history, extending over a period of about 300 million years beginning with the evolution of the ability of insects to fly. With the advent of the success of the Wright brothers, technologists quickly turned their attention from the inspirations and lessons provided by natural models of flying machines to …
Some Systemic Issues In The Development Of The Aerospace Industry Technical Workforce Of The Future, John H. Mcmasters, Russell M. Cummings
Some Systemic Issues In The Development Of The Aerospace Industry Technical Workforce Of The Future, John H. Mcmasters, Russell M. Cummings
Aerospace Engineering
This paper is a continuation of the authors’ previous examinations of a suite of issues surrounding the putative decline in aeronautics in this country. The purpose of this paper is to discuss three specific issues believed to be of particular importance to the future of our industry. The first is the question of how many engineers we may need in our future as we confront the problem of an aging workforce and the globalization of our industry. The second is the question of what skills and abilities these engineers will need to possess as the overall industry continues to evolve. …
Detached-Eddy Simulation Of Slat And Flap Aerodynamics For A High-Lift Wing, Russell M. Cummings, Scott A. Morton, James R. Forsythe
Detached-Eddy Simulation Of Slat And Flap Aerodynamics For A High-Lift Wing, Russell M. Cummings, Scott A. Morton, James R. Forsythe
Aerospace Engineering
Three-dimensional multi-element wings are simulated to investigate slat and flap aerodynamics using Detached-Eddy Simulation. The computations are performed by solving the Navier-Stokes equations on unstructured grids. All of the computed cases include the main wing with a half-span flap deflected to 39 degrees and a three-quarter-span slat deflected to 6 degrees. Computations of the model, which simulates a landing configuration at 10 degrees angle of attack and a chord-based Reynolds number of 3.7 million, are validated with surface pressure measurements acquired at the NASA Ames 7- by 10-Foot Wind Tunnel. The results increase the computational knowledge of how to accurately …
An Embedded Boundary Cartesian Grid Scheme For Viscous Flows Using A New Viscous Wall Boundary Condition Treatment, David D. Marshall, Stephen M. Ruffin
An Embedded Boundary Cartesian Grid Scheme For Viscous Flows Using A New Viscous Wall Boundary Condition Treatment, David D. Marshall, Stephen M. Ruffin
Aerospace Engineering
This work presents a new viscous wall boundary condition technique for embedded Cartesian grid schemes in order to model laminar viscous flows. The development of viscous effects modeling using pure Cartesian grids with cut cells at the surface has been hampered by the widely varying control volume sizes associated with the mesh refinement and the cut cells associated with the solid surface. This scheme removes the cells adjacent to the surface from the control volume formulation. These cells are instead solved via an interpolation technique which utilizes the wall boundary conditions to build the interpolating functions. Two different interpolation techniques …
A New Inviscid Wall Boundary Condition Treatment For Embedded Boundary Cartesian Grid Schemes, David D. Marshall, Stephen M. Ruffin
A New Inviscid Wall Boundary Condition Treatment For Embedded Boundary Cartesian Grid Schemes, David D. Marshall, Stephen M. Ruffin
Aerospace Engineering
This work presents a new inviscid wall boundary condition technique for embedded Cartesian grid schemes. This scheme eliminates the time step restrictions associated with the arbitrarily small control volumes that can result when the surface cuts the Cartesian control volumes. The cells adjacent to the surface are removed from the control volume formulation and are instead solved via an interpolation technique which utilizes the wall boundary conditions to build the interpolating functions. Two different interpolation techniques are presented, one without considering wall curvature and one considering wall curvature. Results are compared to a two-dimensional airfoil case and a three-dimensional wing …