Assessment of time reversal acoustic focusing in a water pipe with relevance to biofouling control

The proliferation of invasive mussel species in water-intake pipelines presents a major challenge for many industries, typically addressed through chemical or mechanical methods. In this work, an alternative acoustic delivery approach is assessed, based on time-reversal focusing in a rigid-walled, water-filled duct. Higher-order modes above cut-on are dispersive, causing broadband pulses to lose peak amplitude over distance through temporal spreading. Numerical simulations using a modal expansion model show that time reversal can instead exploit this dispersive behavior to refocus energy at a chosen location on the pipe wall. Under lightly damped conditions, time-reversal excitation yields impulsive acoustic pressure peaks exceeding 40 times those achieved by single-frequency excitation, with elevated pressures extending over a sizeable region around the focal point. Peak pressure is used here as a representative acoustic metric while acknowledging that the dominant biological mechanism for antifouling remains uncertain. By adjusting the focal waveform duration, a trade-off is demonstrated between peak pressure and pulse repetition frequency, indicating flexibility in how acoustic exposure may be delivered. Although real pipelines exhibit fluid–structure coupling and higher damping, these results help assess the potential of dispersive focusing for acoustic antifouling applications.