Cruise Flight Noise Levels in a Turbojet Transport Airplane

Sound transmission through double cylindrical shells lined with porous material under turbulent boundary layer excitation

“…Substituting the displacement equations (14)- (16) and pressure equations (B.1)-(B.4) into the shell motion equations (4)-(6) and the boundary condition equations (B.5)-(B.11), the unknown modal coefficients vector x ¼ fp 21jn ; p 22jn ; p 31jn ; p 32jn ; p 41jn ; p 42jn ; p 5jn ; u 1mn ; v 1mn ; w 1mn ; u 2mn ; v 2mn ; w 2mn g can be obtained as Appendix C. Deduction of power spectral density of the total kinetic energy of the inner shell…”

“…Substituting the modal expression for the flexural displacement of Eqs. (16) and (20) into Eq. (21) and considering the orthogonality conditions, Eq.…”

On the sensitivity of sound power radiated by aircraft panels to turbulent boundary layer parameters

“…At cruise conditions, turbulent boundary layer pressure fluctuations on the exterior of the fuselage are a major source of noise inside jet aircraft [12,13], and is more significant as the flight Mach number increases, as shown in [14] for subsonic Mach number. The TBL induces vibrations on the fuselage skin, and the vibrating structure radiates noise into the aircraft cabin.…”

Prediction of Turbulent Boundary Layer Induced Noise in the Cabin of a BWB Aircraft

“…Even though these topics have been investigated for many years, there is still space for new developments in understanding the mechanisms of sound transmission and radiation involved in these problems. In particular, the TBL has been identified as the major source of interior noise in jet powered aircraft, while in cruise flight [1,2] -refer to Fig. 1 of [1].…”