Aerodynamic and structural behavior of a joined-wing configuration of a HALE aircraft
by
Valentina Kaloyanova
University of Cincinnati
Coauthors: Rangarajan Sivaji, Urmila Ghia, Karman Ghia

A high-altitude long-endurance mission requires a lightweight vehicle operating at low speeds, high lift and minimum drag. These conditions necessitate high aspect ratio wings. The complex, three-dimensional flow past the joined wing configuration, proposed by AFRL, is simulated. A Reynolds-Averaged Navier-Stokes (RANS) based flow solver, COBALT, is used for the prediction of the aerodynamic behavior. Detailed flow results are obtained for the high-lift configuration with M = 0.6 and a = 12°. While the joined wing provides enhanced structural integrity, it has some adverse effects on the prevailing flow behavior. A small region of flow separation is observed in the vicinity of the joint. Also, a weak oblique shock is observed in a localized region on the aft wing at the joint. The lift distribution also shows a drop in the joint region, suggesting a destabilizing effect of the joint. A detailed finite-element model representing the entire wing structure is developed. All stringers, skin panels, ribs and spars are modeled using the ANSYS Finite Element Software. The payload is incorporated in the model as well. Results of nonlinear static analysis under the fluid load obtained from the aerodynamic analysis are presented. The high aspect ratio and lightweight requirements increase the wing flexibility and lead to a large wing deformation. The stress distribution in the wing is explored. Also, the free vibration mode shapes are examined. A design optimization is ongoing on this innovative joined-wing configuration.

Date received: March 12, 2004

Copyright © 2004 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # canw-08.