Transient study of an optimized waveguide sonic black hole with wave focusing propertiesHamideh Hassanpour Guilvaiee, Abbas Mousavi, Martin Berggren, Eddie Wadbro, Manfred Kaltenbacher and Florian TothActa Acust., 9 (2025) 36DOI: https://doi.org/10.1051/aacus/2025019