Noise radiated from a periodically stiffened cylindrical shell excited by a turbulent boundary layer

Laurent Maxit (1) , Oriol Guasch (2) , Valentin Meyer (3) , Mahmoud Karimi (4)

1 INSA Lyon - Institut National des Sciences Appliquées de Lyon
2 URL - Universitat Ramon Llull [Barcelona]
3 Naval Group Research [Bouguenais]
4 UTS - University of Technology Sydney

This work proposes a semi-analytical method to model the vibroacoustic behavior of submerged cylindrical shells periodically stiffened by axisymmetric frames and excited by a homogeneous and fully developed turbulent boundary layer (TBL). The process requires the computation of the TBL wall-pressure cross spectral density function and the sensitivity functions for stiffened cylindrical shells. The former is deduced from an existent TBL model and the latter are derived from a wavenumber-point reciprocity principle and a spectral formulation of the problem. The stiffeners' dynamic behavior is introduced in the formulation through circumferential admittances that are computed by a standard finite element code using shell elements. Four degrees of freedom are taken into account for the coupling between the shell and the stiffeners: three translation directions and one tangential rotation. To investigate the effect of the stiffeners on the radiated noise, two case studies are considered. The first one examines a fluid-loaded cylindrical shell with regularly spaced simple supports. The influence of Bloch-Floquet waves and the support spacing on the noise radiation are highlighted. The second case study inspects the fluid-loaded cylindrical shell with two different periodic ring stiffeners, namely stiffeners with T-shaped and I-shaped cross-sections. Their influence on the vibroacoustics of the shell is thoroughly analyzed.

Mots clés: stiffened cylindrical shell; turbulent boundary layer; fluid loading; noise prediction; Bloch-Floquet wave; 2

Domaines: Acoustique [physics.class-ph]

Laurent Maxit, Oriol Guasch, Valentin Meyer, Mahmoud Karimi. Noise radiated from a periodically stiffened cylindrical shell excited by a turbulent boundary layer. Journal of Sound and Vibration, 2020, 466, pp.115016. ⟨10.1016/j.jsv.2019.115016⟩. ⟨hal-02414443⟩