Airflow Resistance

The quotient of the air pressure difference across a specimen divided by the volume velocity of airflow through the specimen. The pressure difference and the volume velocity may be either steady or alternating.

The properties of porous materials that absorb sound are related to the viscous resistance offered to small vibratory movements of air. This property can be assessed by passing a controlled airflow through a sample and measuring the flow resistivity in mks rayls/m.

Standard Test Method for Airflow Resistance of Acoustical Materials - ASTM C522

See also: Airflow Resistivity, Specific Airflow Resistance.