Noise Generation Characteristics of a High-lift Swept and Tapered Wing Model

Abstract

In this paper, noise generation from high-lift devices (HLDs) of a sweptand taperedwing model OTOMO2 measured in low speed wind tunnel experiments are discussed. OTOMO2 has a wing section of simplified high-lift configuration rectangular model OTOMO, and also has a planform of a realistic high-lift configuration aircraft model JSM. Main purpose of the experiment was to answer the questions about the influence of model geometry on HLD noise, which remained in our previous research using the rectangular model OTOMO. Results of the far-field noise measurement in RTRI-Maibara low noise wind tunnel and noise source maps obtained in JAXA-LWT2 low speed wind tunnel are mainly used. Comparison of narrow band spectra of the far-field SPL and noise source maps for the approach, the flap-only-deployed and the slat-only-deployed configurations showed characteristics of the noise generation of the flap-edge and the slat. One of the most remarkable finding was the existence of the multiple tonal component (MTP) in the slat noise spectrum in sweptand tapered-model geometry. The movement of the MTP noise sources along the spanwise location was observed, which was similar phenomenon to the rectangular model geometry. However, for the sweptand tapered-wing model, it is considered that the flow field which is suitable for the MTP generation is produced more locally and it changes continuously along spanwise direction with the variation of the angle of attack. The noise generation of the flap-edge in the sweptand tapered-model geometry was also different from that of the rectangular model geometry because there was the angle of attack dependency. Then it is suggested that there probably existed three different noise sources around the flap-edge.