A volume penalization method for acoustic and aeroacoustic simulation of solid and porous bluff bodies

This work presents a computational method for acoustic and aeroacoustic simulations, using an immersed boundary method to model porous and solid objects. The approach uses a version of the Brinkman-type volume penalization method in combination with an effective volume to solve the full compressible Navier–Stokes equations employing finite-differences in the time domain. The provided framework enables multiple approaches for modeling objects, which are validated and systematically compared in terms of their associated error convergence. Utilizing the effective volume approach allows acoustic simulations to reach up to third-order convergence, enhancing the accuracy of wave propagation modeling. The methodology is demonstrated for the aeroacoustic sound generated by the flow around a porous-coated cylinder at a Reynolds number of $Re=99000$. A sensitivity study validates the expected importance of the modeling parameters. Results from the three-dimensional simulations involving two porous coatings with each two diameters exhibit good agreement with experimental data, confirming the validity and reliability of the approach.