Research on wave transmission characteristics in fluid-filled elastic pipelines using a stiffness pre-scaled hybrid method

The prediction of the acoustic transmission characteristics of silencers is one of the fundamental aspects of pipeline noise control design. Based on classical studies in duct acoustics, a series of prediction methods have been established and widely applied in rigid-walled duct systems. However, in fluid-filled elastic pipelines, the strong coupling between the pipe wall and the fluid makes wave characteristics highly complex. Consequently, characterizing these wave characteristics becomes significantly more difficult, limiting the applicability of conventional prediction methods. To address this, the present study develops an accurate and more convenient method for predicting the acoustic transmission characteristics of silencers inserted in fluid-filled elastic pipelines. This method combines waveguide approaches with numerical techniques, enabling analytical insights via waveguide modes while retaining computational efficiency. To overcome numerical issues arising from the large property differences between the fluid and the pipe wall, a stiffness pre-scaling approach is proposed. Using this approach, the obtained results of acoustic transmission characteristics show good agreement with existing literature, thus validating the method’s accuracy. Further calculations indicate that the elastic effects of the walls influence the axial wave velocity within the pipeline, significantly affecting the noise reduction performance of chamber-type acoustic reflectors.