Non-negative intensity formulations for stochastically excited finite structures

Area of Science:

• Acoustics
• Vibrational Analysis
• Computational Mechanics

Background:

• Non-negative intensity (NNI) identifies key sound power radiating areas on vibrating structures.
• Existing NNI methods are limited to deterministic loads or infinite structures under stochastic excitation.
• A gap exists for calculating NNI in finite structures subjected to stochastic excitation, crucial for real-world engineering problems.

Purpose of the Study:

• To develop novel formulations for calculating NNI in finite structures under stochastic excitation.
• To address engineering applications involving flow-induced vibrations and machinery noise.
• To enable accurate identification of sound power contributions from finite structures in complex environments.

Main Methods:

• An analytical approach using wavenumber space formulation.
• A numerical approach utilizing realizations of deterministic wall pressure fields.
• Application to baffled and unbaffled finite panels under turbulent boundary layer excitation.

Main Results:

• Successful calculation of NNI for finite structures under stochastic excitation.
• Comparison of results from both proposed analytical and numerical formulations.
• Validation against previous experimental or numerical investigations.

Conclusions:

• The proposed formulations effectively calculate NNI for finite structures under stochastic excitation.
• These methods fill a critical gap in structural acoustics and vibration analysis.
• The findings have significant implications for noise control and structural design in engineering applications.