An acoustic cloaking design considering flow effects by using topology optimization

Abstract

A topology optimization method is utilized to design an acoustic cloak in the presence of background mean flows, highlighting both the scientific significance and practical importance of acoustic invisibility in fluids. This study focuses on understanding the inherent physical mechanism and considering realistic constraints for actual manufacturing, ultimately inspiring the development of an optimized cloak that is available for practical fabrication in the presence of flows. Here, we use the density-based topology optimization to assign specified materials and impose practical constraints on the material allocation to achieve the desired cloaking performance. The optimization problem is then efficiently solved using the gradient-based globally convergent method of moving asymptotes, leveraging the derivative information from the finite element simulation studies of the linearized acoustic potential equation. To validate the proposed method, several numerical simulations are conducted, exploring different frequencies, incident flow speeds, and incident angles of flow. The results confirm the effectiveness and efficiency of the optimization method, expanding the range of applications of the acoustic cloak and contributing to a deepened physical understanding of how it manipulates sound waves in flows.