Near-surface topology of unmanned combat air vehicle planform: Reynolds number dependence

Elkhoury, M
Yavuz, Mehmet Metin
Rockwell, D
The Reynolds number dependence of the near-surface flow structure and topology on a representative unmanned combat air vehicle planform is characterized using a technique of high-image-density particle image velocimetry, to complement classical dye visualization. Patterns of streamline topology, including bifurcation lines, as well as contours of streamwise and transverse velocity, surface-normal vorticity, and Reynolds stress correlation, all immediately adjacent to the surface of the planform, provide quantitative indicators. At low angle of attack, these indicators show significant alterations with Reynolds number, in accord with large variations of patterns of vortex breakdown and vortex interaction visualized by dye and substantial alterations of flow patterns in the crossflow plane, including reattachment phenomena, which are interpreted with patterns of velocity, streamlines, and streamwise vorticity. On the other hand, at moderate angle of attack, the near-surface quantitative indicators show much less sensitivity to Reynolds number, which is in line with weak variations of the onset of vortex breakdown with changes in Reynolds number.


Near-surface topology and flow structure on a delta wing
Yavuz, Mehmet Metin; Rockwell, D (American Institute of Aeronautics and Astronautics (AIAA), 2004-02-01)
The streamlines, and the corresponding patterns of velocity and vorticity, are characterized on a plane immediately adjacent to the surface of a delta wing using a laser-based technique of high-image-density particle image velocimetry. This technique provides the sequence of instantaneous states, as well as the corresponding time-averaged state, of the near-surface streamline topology and the associated critical points. These topological features are interpreted in terms of patterns of averaged and unsteady...
Computational study of subsonic flow over a delta canard-wing-body configuration
Tuncer, İsmail Hakkı (American Institute of Aeronautics and Astronautics (AIAA), 1998-07-01)
Subsonic flowfields over a close-coupled, delta canard-wing-body configuration at angles of attack of 20, 24,2, and 30 deg are computed using the OVERFLOW Navier-Stokes solver Computed flowfields are presented in terms of particle traces, surface streamlines, and leeward-side surface pressure distributions for the canard-on and -off configurations. The interaction between the canard and the wing vortices, wing vortex breakdown, and the influence of the canard on vortex breakdown are identified, The comparis...
Time-domain calculation of sound propagation in lined ducts with sheared flows
Özyörük, Yusuf (American Institute of Aeronautics and Astronautics (AIAA), 2000-05-01)
A recent application of the time-domain equivalent of the classical acoustic impedance condition, i.e., the particle displacement continuity equation, to numerical simulations of a Bow-impedance tube in the time domain yielded reasonably good results with uniform mean flows. The present paper extends this application to include sheared mean-flow effects on sound propagation over acoustically treated walls. To assess the prediction improvements with sheared flows, especially at relatively high Mach numbers, ...
Nonlinear flutter calculations using finite elements in a direct Eulerian-Lagrangian formulation
Seber, Guclu; Bendiksen, Oddvar O. (American Institute of Aeronautics and Astronautics (AIAA), 2008-06-01)
A fully nonlinear aeroelastic formulation of the direct Eulerian-Lagrangian computational scheme is presented in which both structural and aerodynamic nonlinearities are treated without approximations. The method is direct in the sense that the calculations are done at the finite element level, both in the fluid and structural domains, and the fluid-structure system is time-marched as a single dynamic system using a multistage Runge-Kutta scheme. The exact nonlinear boundary condition at the fluid-structure...
Aerodynamic design and optimization of horizontal axis wind turbines by using bem theory and genetic algorithm
Ceyhan, Özlem; Tuncer, İsmail Hakkı; Department of Aerospace Engineering (2008)
An aerodynamic design and optimization tool for wind turbines is developed by using both Blade Element Momentum (BEM) Theory and Genetic Algorithm. Turbine blades are optimized for the maximum power production for a given wind speed, a rotational speed, a number of blades and a blade radius. The optimization variables are taken as a fixed number of sectional airfoil profiles, chord lengths, and twist angles along the blade span. The airfoil profiles and their aerodynamic data are taken from an airfoil datab...
Citation Formats
M. Elkhoury, M. M. Yavuz, and D. Rockwell, “Near-surface topology of unmanned combat air vehicle planform: Reynolds number dependence,” JOURNAL OF AIRCRAFT, pp. 1318–1330, 2005, Accessed: 00, 2020. [Online]. Available: