NUMERICAL-SIMULATION OF STEADY AND UNSTEADY, VORTICITY-DOMINATED AERODYNAMIC INTERFERENCE

The problem of modeling steady and unsteady aerodynamic interference is discussed. A configuration resembling the X-29 is used as an example. The general unsteady vortex-lattice method is used to model the flowfield. By considering the components operating alone and as members of the complete configuration, we demonstrate the importance of accurately simulating the wakes of the upstream components. The wakes of the canards as well as the canards themselves have a strong negative influence on the lift generated by the main wing; the main wing has a positive influence on the lift generated by the canards. The forward sweep of the main wing tends to focus the generated upwash in the vicinity of the canards. It is shown that the maximum influence of the vorticity shed from the canards does not develop until the shed vorticity convects downstream directly over the main wing. The general unsteady vortex-lattice method appears to be a reasonably accurate model of closely coupled, vorticity-dominated flowfields as long as the lines of the separation are known and vortex bursting does not occur near the wings.