Limit cycle oscillations of aeroelastic systems with internal friction in the transonic domain - Experimental results

Abstract

This paper reports on the design, fabrication, and testing of a friction generating device connected to an airfoil to assess the effects of internal friction on limit cycle oscillations. Preliminary shaker testing in the ASU vibrations laboratory successfully validated the design. Full blown testing was then carried out at DLR in the DNW-TWG transonic wind tunnel and limit cycle oscillations with internal friction effects were observed and measured. These first measurements demonstrated a slight benefit of friction but also showed the subcritical nature of the observed limit cycle oscillations which is clarified. A different design is proposed for future tests that should lead to supercritical limit cycle oscillations.