The Acoustical Behavior of Contra-Rotating Fan

Table 2

The highest sound pressure of four axial spacing points.

Axial spacing	Probe-1	Probe-2	Probe-3	Probe-4
0.5 chord	92 dB	100 dB	95 dB	100 dB
0.65 chord	85 dB	90 dB	95 dB	95 dB
0.75 chord	85 dB	95 dB	98 dB	92 dB
1 chord	85 dB	97 dB	98 dB	90 dB