Acoustic simulation using a frequency domain FEM with air absorption

Recently, the applicability of wave-based acoustic simulations that solve the Helmholtz equation has been expanding drastically to high-frequency ranges and large spaces with the development of higher efficient methods. Although standard acoustic simulations generally solve the lossless Helmholtz equation, considering the air absorption effect will contribute to increasing prediction accuracy at higher frequencies. This paper presents an accuracy and efficiency assessment of frequency-domain FEM (FD-FEM) acoustic simulations with air absorption effect based on the ISO 9613-1 model. First, the accuracy of FD-FEM, including the air absorption model, is verified at frequencies up to 20 kHz via a plane wave propagation problem in a long duct. Then, we will demonstrate its efficiency via a real-scale 2D office problem. Results reveal that considering air absorption can increase computational efficiency for higher frequencies as an additional benefit.