Sound radiation from impact-driven raked piles.

Area of Science:

• Acoustics
• Environmental Engineering
• Computational Mechanics

Background:

• Impact pile driving generates sound with directional characteristics.
• Raked piles, due to their angled orientation, introduce azimuthal dependence in radiated sound fields.
• Accurate prediction of underwater noise is crucial for environmental impact assessments.

Purpose of the Study:

• To model and predict the sound radiation from impact pile driving of raked piles.
• To investigate the azimuthal dependence of the sound field.
• To develop an efficient modeling approach that avoids computationally expensive 3D models.

Main Methods:

• Utilized a finite element method (FEM) model for the pile and near-field sound.
• Employed a normal mode model to predict far-field sound radiation.
• Developed an equivalent axisymmetric FEM model by matching radiated fields to phased point sources and offsetting locations.

Main Results:

• The equivalent axisymmetric FEM model accurately predicted the azimuthal dependence of the radiated sound field.
• This simplified model closely matched predictions from a fully 3D FEM model.
• Numerical results were validated against acoustic measurements from Western Australia.

Conclusions:

• An equivalent axisymmetric FEM model is an efficient and accurate method for predicting sound radiation from raked piles.
• This approach simplifies complex acoustic modeling for underwater noise from pile driving.
• The findings support improved environmental monitoring and mitigation strategies for marine construction.