A model for calculating the air flow resistivity of glass fiber felt

• A series of simplifying assumptions about the complex structure of glass fiber felt have been used to derive a model.
• Fiber diameter, bulk density and porosity are considered in this model for flow resistivity.
• The resulting predictions of flow resistivity have been found to agree well with measurements.
• Resin content is considered in this model, and considering the amount of resin can accurately predict air flow resistivity.

The acoustical properties of fiber materials are mainly determined by the air flow resistivity. In this paper a model for calculating the air flow resistivity of glass fiber felt is presented. According to this model the air flow resistivity depends on the mean spacing of the fibers, the amount of resin bonding and the physical properties of air. Expressions for predicting the air flow resistivity of glass fiber felt are derived. It is demonstrated that the model gives predictions that are reasonably close to direct measurements.