The effect of external mean flow on sound transmission through double-walled cylindrical shells lined with poroelastic material

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

“…3 and 5, it can be seen that the air gap is important for reducing of sound transmission in the frequency range between the ring frequency and acoustic coincidence frequency. This phenomenon is also observed when a plane wave transmits through sandwich structures [4,11,12].…”

“…The airborne wave is the dominant wave in the UU configuration [40]. This approach proposed by Lee et al [40] has also been used by the present authors [12] for studying transmission of plane waves through infinite cylindrical shells. For brevity, the detail of this method will not be repeated here.…”

“…L 1 , L 2 and L 3 are linear differential operators for the circular cylindrical shell which can be found in references [12,41]. Fig.…”

“…Considering the equations of motion (4)-(6) and boundary conditions equation (12), the solutions for the displacement field can be expressed as…”

On sound transmission through double-walled cylindrical shells lined with poroelastic material: Comparison with Zhou׳s results and further effect of external mean flow

“…In the analytical modelling of this problem, cylindrical shell structures need to be considered to account for aircraft fuselage geometry (e.g. [1][2][3][4][5]); the effects of external flow must be taken into account for flight conditions [1,[6][7][8][9][10][11][12]. Moreover, sound absorptive materials can be included within the sandwich core to enhance the sound insulation performance of such structures [1,[10][11][12][13][14][15].…”