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Full-Text Articles in Engineering
Fifty Years Of Hypersonics: Where We've Been, Where We're Going, John J. Bertin, Russell M. Cummings
Fifty Years Of Hypersonics: Where We've Been, Where We're Going, John J. Bertin, Russell M. Cummings
Aerospace Engineering
Hypersonic flight has been with us since 22 September 1963, when Robert M. White flew the North American X-15 at 4520 mph at an altitude of 354,200 ft—a Mach number of 6.7! This remarkable achievement was accomplished over six decades due to intensive research and development by a large number of scientists and engineers. In spite of that momentous achievement, designers have found the hypersonic environment to be harsh and non-forgiving. New programs since the 1960s have often uncovered the unknown unknowns, usually the hard way—early flights of new systems have often revealed problems of which the designers were …
Computational Challenges In High Angle Of Attack Flow Prediction, Russell M. Cummings, James R. Forsythe, Scott A. Morton, Kyle D. Squires
Computational Challenges In High Angle Of Attack Flow Prediction, Russell M. Cummings, James R. Forsythe, Scott A. Morton, Kyle D. Squires
Aerospace Engineering
Aircraft aerodynamics have been predicted using computational fluid dynamics for a number of years. While viscous flow computations for cruise conditions have become commonplace, the non-linear effects that take place at high angles of attack are much more difficult to predict. A variety of difficulties arise when performing these computations, including challenges in properly modeling turbulence and transition for vortical and massively separated flows, the need to use appropriate numerical algorithms if flow asymmetry is possible, and the difficulties in creating grids that allow for accurate simulation of the flowfield. These issues are addressed and recommendations are made for further …
Multidisciplinary Applications Of Detached-Eddy Simulation To Separated Flows At High Reynolds Numbers, Scott A. Morton, Matt Steenman, Russell M. Cummings, James R. Forsythe, Kenneth E. Wurtzler, Kyle D. Squires, Shawn H. Woodson, Phillippe R. Spalart
Multidisciplinary Applications Of Detached-Eddy Simulation To Separated Flows At High Reynolds Numbers, Scott A. Morton, Matt Steenman, Russell M. Cummings, James R. Forsythe, Kenneth E. Wurtzler, Kyle D. Squires, Shawn H. Woodson, Phillippe R. Spalart
Aerospace Engineering
We focus on multidisciplinary applications of detached-eddy simulation (DES), principally flight mechanics and aeroelasticity. Specifically, the lateral instability (known as abrupt wing stall) of the preproduction F/A-18E is reproduced using DES, including the unsteady shock motion. The presence of low frequency pressure oscillations due to shock motion in the current simulations and the experiments motivated a full aircraft calculation, which showed low frequency high-magnitude rolling moments that could be a significant contributor to the abrupt wing stall phenomenon. DES is also applied to the F-18 high angle of attack research vehicle (HARV) at a moderate angle of attack to reproduce …
Computational Simulation And Piv Measurements Of The Laminar Vortical Flowfield For A Delta Wing At High Angle Of Attack, Russell M. Cummings, Scott A. Morton, Stefan G. Siegel
Computational Simulation And Piv Measurements Of The Laminar Vortical Flowfield For A Delta Wing At High Angle Of Attack, Russell M. Cummings, Scott A. Morton, Stefan G. Siegel
Aerospace Engineering
The low-speed, laminar flowfield for a 70°-sweep delta wing is investigated. Solutions to the unsteady, three-dimensional, compressible Navier-Stokes equations were obtained on an unstructured grid to match results from an experiment performed in a water tunnel. The experiment was conducted with the delta wing at an angle of attack of 35° and the freestream flow at a root-chord Reynolds number of 40,700. The computational results are analyzed and compared with the experimental results in order to show how computations and experiments can be conducted in a synergistic fashion. Details about the primary vortex location, vortex burst, secondary vortex, and shear …
Des Grid Resolution Issues For Vortical Flows On A Delta Wing And An F-18c, Scott A. Morton, Mathew B. Steenman, Russell M. Cummings, James R. Forsythe
Des Grid Resolution Issues For Vortical Flows On A Delta Wing And An F-18c, Scott A. Morton, Mathew B. Steenman, Russell M. Cummings, James R. Forsythe
Aerospace Engineering
An assessment of unstructured grids for use in Detached-Eddy Simulations (DES) of vortical flowfields over two configurations, a 70 degree delta wing and an F-18C are presented. The role of the grid in detached eddy simulations of vortical flowfields, including complex features such as vortex breakdown, is assessed on a delta wing with comparison to wind tunnel data. Adaptive mesh refinement is applied to the delta wing grid to improve the focus region aft of the vortex breakdown where massively separated flow exists and unsteady pressures are generated that could impact the loads on vertical tails of more complex configurations. …
A Multifaceted Approach To The Aiaa Foundation Undergraduate Team Aircraft Design Competition, Russell M. Cummings, Aaron R. Byerley
A Multifaceted Approach To The Aiaa Foundation Undergraduate Team Aircraft Design Competition, Russell M. Cummings, Aaron R. Byerley
Aerospace Engineering
A multifaceted, novel approach was used to help students create entries for the AIAA Foundation Undergraduate Team Aircraft Design Competition. Each entry involved the design, analysis, construction, and testing of the aircraft. Three groups were involved for each airplane: the first group was responsible for the airframe, the second group was responsible for the engine, and the third group was responsible for the construction and flight testing of a radio-controlled flying model. There was an overall Chief Executive Officer who insured that engine-airframe integration issues were addressed. Students from a variety of majors, both technical and non-technical, participated in various …