James R. Forsythe

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An understanding of the vortical structures which comprise the vortical flowfield around slender bodies is essential for the development of highly maneuverable and high angle of attack flight. This is primarily due to the physical limits these phenomena impose on aircraft and missile s at extreme flight conditions. Demands for more maneuverable air vehicles(More)
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(More)
The flowfield around a 6:1 prolate spheroid at angle of attack is predicted using solutions of the Reynolds-averaged Navier-Stokes (RANS) equations and detached-eddy simulation (DES). The calculations were performed at a Reynolds number of 4.2310, the flow is tripped at x/L50.2, and the angle of attack a is varied from 10 to 20 deg. RANS calculations are(More)
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(More)
Predictions of the flow over a wall-mounted hump are obtained using solutions of the Reynolds-averaged Navier-Stokes (RANS) equations and Detached-Eddy Simulation (DES). The upstream solution is characterized by a two-dimensional turbulent boundary layer with a thickness approximately half of the maximum hump thickness measured at a location about two chord(More)
Detached-eddy simulation is applied to an axisymmetric base flow at supersonic conditions. Detached-eddy simulation is a hybrid approach to modeling turbulence that combines the best features of the Reynolds-averaged Navier-Stokes and large-eddy simulation approaches. In the Reynolds-averaged mode, the model is currently based on either the Spalart-Allmaras(More)
An assessment of unstructured grids for use in Detached-Eddy Simulation (and more generally in Large-Eddy Simulation) of massively separated ows is presented. The role of the grid, its generation and re nement, are considered via calculation of three high-Reynolds number turbulent ows of aerodynamic interest: the massively separated ow over a forebody in(More)
Predictions of the massively separated flow around a rectangular ogive forebody are obtained using Detached-Eddy Simulation (DES) and solutions of the unsteady Reynolds-averaged Navier-Stokes (URANS) equations. Based on the body width/diameter D, the forebody length is 2D while the length of the aft section is 4D. The cross-section is a rounded-corner(More)
Predictions of the flow around the Ground Transportation System (GTS) are obtained from Detached-Eddy Simulation (DES) and from the Reynolds-averaged Navier-Stokes (RANS) equations. Two methods are compared with experiment, but only one grid is used, as the work is in progress. Grid variations will be needed. The computations are performed at a Reynolds(More)
A successful fielding of computation-based engineering (CBE) software requires quality assurance to be built into the fabric of capability development and deployment processes. Good software quality is an emergent property of the healthy interplay among CBE software development teams, testing teams, user support, and training teams, with the vital notion of(More)