Measured scattering and absorption coefficients of an area expansion with flow.

Measured scattering coefficients of an area expansion for six different flow speeds. Measured absorption coefficients of an area expansion for six different flow speeds.

The coefficients are obtained for two assumptions, expanded and non-expanded flow downstream of the area expansion. The coefficients have been measured for plane waves (up to a frequency 2300 Hz), with an area expansion ratio of 0.3086. The following six upstream Mach numbers have been used to obtain the scattering matrices, M=0.00, 0.05, 0.10, 0.15, 0.20 and 0.25.