Examination of the influence of altitude and speed on fuselage hull excitation parameters induced by the turbulent boundary layer at cruise flight conditions

Abstract

In this paper, flight test measurements are evaluated. The influence of different flight conditions on characteristic parameters concerning the aircraft hull excitement aptitude by the flow is examined. Pressure fluctuation data were acquired from a flight test campaign using a pressure transducer array. In a first evaluation, data have been analyzed for a single flight condition at Ma = 0.78 and an altitude of h = 35,000 ft. Characteristic coherence decay functions and their parameters were determined using the predominant flow direction for each frequency. This evaluation of characteristics of the pressure fluctuations is now applied to different flight altitudes and -speeds. The influence of exterior pressure and flow speed on coherence decay function parameters and the cohvective characteristics will be examined. This way, conclusions about the variation of these decay function parameters with flight attitude can be drawn. Also, the change in charactersitic of the convective transport of pressure fluctuations with flight condition is examined.