Leaky wave characterisation using spectral methods.

Area of Science:

• Physics
• Wave Mechanics
• Materials Science

Background:

• Leaky waves guide energy along structures, but wave speed mismatches cause energy leakage and attenuation.
• Accurate identification of leaky waves is vital for selecting modes and frequencies in non-destructive evaluation (NDE) techniques.
• Traditional methods for identifying leaky waves face challenges with numerical conditioning and handling exponential growth.

Purpose of the Study:

• To develop an accurate, fast, and efficient method for identifying leaky waves.
• To address the limitations of existing root-finding and numerical methods for leaky wave analysis.
• To enable precise selection of modes and frequencies for NDE applications.

Main Methods:

• Adaptation of a spectral collocation method to find exponentially growing solutions.
• Implementation of a mapping in the fluid region to manage the physical solution's exponential growth at infinity.
• Study of leaky Lamb waves in an elastic waveguide between two fluids.

Main Results:

• The adapted spectral collocation method accurately identifies leaky waves and their dispersion properties.
• The method efficiently handles exponentially growing solutions, overcoming previous numerical challenges.
• Validation of the technique using the commercial software 'disperse'.

Conclusions:

• The modified spectral collocation method provides an accurate and efficient approach for leaky wave analysis.
• This advancement is critical for improving the effectiveness of non-destructive evaluation techniques.
• The study demonstrates a robust solution for identifying leaky waves in fluid-immersed elastic waveguides.