Composition-Tuned Acoustic Damping in He–Ar Mix-tures via Carbon Nanotube Absorption: A Molecular Dynamics Study
پذیرفته شده برای ارائه شفاهی
کد مقاله : 1042-ISAV2025 (R1)
نویسندگان
1دانشگاه یزد
2دانشکده علوم، دانشگاه یزد
3دانشکده مهندسی مکانیک، دانشگاه یزد
چکیده
Noise pollution is a critical environmental concern, driving the need for compact nanoscale acoustic absorbers. Carbon nanotubes (CNTs) are promising candidates due to their high stiffness, tunable geometry, and strong gas-solid coupling. This study employs molecular dynamics (MD) simulations to investigate longitudinal wave propagation and attenuation in helium-argon mixtures (He mole fraction: 0.0 to 1.0), both with and without a single-walled CNT absorber. The results show that sound velocity increases monotonically with helium fraction, consistent with the reduc-tion in mean molar mass. In contrast, the attenuation coefficient exhibits a non-monotonic depend-ence, peaking near the equimolar mixture due to enhanced Ar–He collision rates. The presence of the CNT modifies attenuation in a composition-dependent manner: at low helium fractions (≤0.5), total attenuation is suppressed because of standing-wave nodes and strong gas-phase damping, while at high helium fractions (≥0.7), attenuation is amplified as energetic helium atoms efficiently transfer momentum to the CNT. These findings clarify the microscopic mechanisms of nanoscale acoustic absorption and provide valuable MD benchmarks for the rational design of next-generation acoustic devices.
کلیدواژه ها
Title
Composition-Tuned Acoustic Damping in He–Ar Mix-tures via Carbon Nanotube Absorption: A Molecular Dynamics Study
Authors
Fahimeh Mokhtari, Mohammad Kamalvand, Mohammad Mehdi Jalili
Abstract
Noise pollution is a critical environmental concern, driving the need for compact nanoscale acoustic absorbers. Carbon nanotubes (CNTs) are promising candidates due to their high stiffness, tunable geometry, and strong gas-solid coupling. This study employs molecular dynamics (MD) simulations to investigate longitudinal wave propagation and attenuation in helium-argon mixtures (He mole fraction: 0.0 to 1.0), both with and without a single-walled CNT absorber. The results show that sound velocity increases monotonically with helium fraction, consistent with the reduc-tion in mean molar mass. In contrast, the attenuation coefficient exhibits a non-monotonic depend-ence, peaking near the equimolar mixture due to enhanced Ar–He collision rates. The presence of the CNT modifies attenuation in a composition-dependent manner: at low helium fractions (≤0.5), total attenuation is suppressed because of standing-wave nodes and strong gas-phase damping, while at high helium fractions (≥0.7), attenuation is amplified as energetic helium atoms efficiently transfer momentum to the CNT. These findings clarify the microscopic mechanisms of nanoscale acoustic absorption and provide valuable MD benchmarks for the rational design of next-generation acoustic devices.
Keywords
Acoustic attenuation, Helium–argon mixtures, Standing waves, Gas–nanostructure interac-tions