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Numerical Simulation of Nonlinear Thermoviscous Acoustic Wave Propagation

In behind-the-ear hearing aids, sound levels exceeding 140 dB SPL occur in the narrow tubes. This causes nonlinear distortion and thermoviscous attenuation. In this ICA publication, J.A. de Jong and E.R. Kuipers present a 1D model that efficiently predicts these effects.

1D Modeling of Nonlinear Thermoviscous Waves

In behind-the-ear (BTE) hearing aids, sound entering narrow tubes (approximately 1 mm) reaches levels above 140 dB SPL. This leads to nonlinear distortion and thermoviscous losses. Because full CFD is computationally intensive, the authors implement a 1D model based on Chester. The half-order time derivative for boundary layer losses is calculated locally using a diffusive approximation. By optimizing the quadrature coefficients against Tijdeman’s solution, the dispersion error remains below 0.3%. Verification using 2D-CFD (OpenFOAM) on a quarter-wave resonator shows close agreement.

Citation for the publication

  • Authors: Jan Albertus de Jong (ASCEE) & Erwin Reinder Kuipers (Sonova AG)

  • Publication: Proceedings of the 23rd International Congress on Acoustics (ICA 2019)

  • Location & Date: Aachen, Germany (September 9–13, 2019)

  • Research Partner / Funding: Sonova AG

  • Keywords: Nonlinear acoustics, thermoviscous losses, pipe acoustics, hearing aids (BTE)

  • Download / View the paper (PDF)

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