The effect of nose bluntness of a low-boom configuration on sonic-boom

The effect of the nose bluntness of an aircraft on sonic-boom intensities is described. In order to clarify the effect of the nose bluntness, the boom intensity of a low-drag and a low-boom configuration are first predicted. The pressure signatures for near-field are simulated by a three-dimensional Euler finite difference code. The calculated nearfield signatures are extrapolated to far-field by the Thomas's waveform parameter method based on a quasi-linear theory. As a result, it is indicated that the boom intensity of a low-boom configuration is about 1.0 [psf] which is about 0.5 [psf] smaller than that of a low-drag configuration in the case of same lift coefficient. A trade off study between the sonicboom intensity and the aircraft drag is next done by using the Darden's boom minimization theory. The fuselage geometry of the low-boom configuration is modified to change the nose bluntness. It is clarified that the parameter yf/L which represents the bluntness of the nose configuration in the Darden's theory has proper values between 0.04 and 0.08.