Numerical study to investigate the thermal characteristic length with coupled CFD-FEM simulations

This paper introduces a new technique for directly calculating the thermal characteristic length (Lambda ') of porous materials, addressing a critical parameter required for accurate acoustic simulations during vehicle development. The proposed method offers improved practicality over existing approaches. The research seeks to overcome the limitations of current methods, proposing a coupled CFD-FEA approach within a fluid-structure interaction (FSI) simulation framework. By incorporating both fluid temperature and the fundamental definition of characteristic length, this formulation enables the direct calculation of Lambda '. The validity of the method is established through specific tests conducted on ten reconstructed material samples. The proposed approach outperforms measurement techniques and established formulas, offering enhanced accuracy while overcoming the limitations of experimental repeatability. The study demonstrates the universal nature of characteristic curves across various flow regimes, ensuring consistent parameter determination under different flow conditions and sample sizes. Additionally, the research highlights the significant influence of structure deformation, regardless of flow regime, sample size, and flow direction. This paper advances the comprehension of characteristic parameters across diverse conditions by presenting a new method that enhances practicality, accuracy, and applicability to vehicle acoustic simulations.