Experimental Study on Relative Flow Regime and Broadband Noise of a Propeller Fan

Soichi Sasaki (1) , Hisanari Hidaka (1)

1 Nagasaki University

The aim of this study is to clarify the relationship between the broadband noise from the low frequency to transition frequency domain generated from the propeller fan and the relative flow regime. In the off design operation condition, the velocity fluctuation having a lower frequency than the blade passing frequency was formed at the leading edge of the blade tip side. The low frequency broadband noise in the off design operation condition has feasibility to generate at the leading edge by adjoined blade interference of the lower frequency than the blade passing frequency. The major factor of the fan noise in the design operation condition was the broadband noise in the transition frequency. From the analysis of CFD, we clarified when the unstable wave due to Karman vortex shedding resonates with the air column resonance frequency made by the blade passage, the pressure fluctuation having a specific frequency is enhanced. These results indicated that the noise in the specific frequency band increased, even though the fan is operated in the design flow rate, when the air column resonance in the blade passage was superimposed to the span direction.

Mots clés: aeroacoustics; broadband noise; propeller; fan

Domaines: Mécanique des structures [physics.class-ph]

Soichi Sasaki, Hisanari Hidaka. Experimental Study on Relative Flow Regime and Broadband Noise of a Propeller Fan. 17th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery (ISROMAC2017), Dec 2017, Maui, United States. ⟨hal-02387675⟩