Sound Radiation by a Baffled Panel Subject to TBL Exciation

The formulation presented in the section above has provided a general modelling framework for the structural-acoustic coupled response of a closed shell, which is excited by the pressure field exerted by the TBL fluid flow. A simplified model problem is now considered in order to identify the principal properties of the interior sound radiation generated by a flexible wall subject to a TBL pressure field. As schematically shown in Figure 7, the model problem considered here comprises a thin flat rectangular panel, which is baffled and immerged in an unbounded fluid. The panel is excited by a TBL pressure field on the outer side and radiates sound to the inner side. The panel is considered to be immerged in air, in which case, based on the considerations presented in Section 1.5, the so called “weakly coupled response” is derived by neglecting the fluid loading effects on both sides of the panel. This type of model provides the principal features for the sound radiation to the interior of a large and heavily damped enclosure produced by a section of the enclosure wall.

For this type of problem, the interior sound radiation is expressed in terms of the time-averaged total radiated sound power Pr, which can be derived with the following formula:

[29] Also for this system, as shown in shown in Figure 7, the standard notation used for the Helmholtz integral equation is used where the vector n points away from the acoustic domain, thus vn (x s) = – W (x s) .

[30] NVH stands for Noise Vibration Harness