Effect of Sweep on Buffet over Novel Wing Planforms

Abstract

The results of wind tunnel testscarried outon two semispan models, with sweep angles of 40 and 60 deg, arepresented. The planforms of the models have features consistent with likely cone gurations of future low-observable aircraft. An examination of pressure e uctuations over such aircraft is of particular importance because of the dife culties involved in altering such aircraft late in their design to address problems of excessive buffeting. The dynamic calibration of surface pressure tappings has allowed both mean and unsteady pressures to be measured. Unsteady pressure readings have been analyzed to derive both root-mean-square pressures and spectral information. Peaks in the spanwise root-mean-square pressure distribution are found inboard of the leading edge vortex for each wing. Two additional peaks are present over the more highly swept wing. One of these peaks is coincident with the secondary separation; another is found outboard of the leading edge vortex.