Topology optimized design for low-frequency ventilation barrier based on Helmholtz resonator

Efficient attenuation of low-frequency sound (<1000 Hz) while maintaining unrestricted airflow remains a long-standing pursuit in noise control engineering. Here, a ventilation barrier is integrated with a Helmholtz resonator and an open channel. A density-based topology optimization approach is employed to distribute material within the resonant cavity, effectively reducing noise at target frequencies. For frequencies of 550 Hz, 500 Hz, 450 Hz, 400 Hz, and 350 Hz, the optimized designs achieve transmission losses exceeding 25 dB. Multiple optimized solutions for the same frequencies show minimal variation in sound attenuation performance. Sound pressure and particle velocity distributions are analyzed to reveal the sound insulation mechanisms of the optimized units. Acoustic experiments validate the optimized designs, with results in agreement with numerical calculations. Furthermore, a 48.1% open channel area is maintained, ensuring efficient airflow. Ventilation tests confirm effective air circulation, demonstrating advantages over conventional sound barriers and expanding potential applications in diverse ventilation scenarios.