An in-depth investigation into the effects of sweep on the aerodynamic and aeroacoustic performance of a rotor is carried out in this study. Dynamically similar swept and unswept rotor designs were tested and compared at the Virginia Tech Open Jet Wind tunnel for varying rotational rates and inflow speeds. It was observed that introducing sweep did not compromise the aerodynamic performance. Noise measurements indicated that the swept rotor has a lower noise signature in the mid-frequency range (∼0.5-5 kHz). Further, the broadband and tonal components were separately studied and it was observed that the noise reduction in the swept rotor is largely due to reduced broadband noise. Additionally, a URANS CFD analysis was carried out using the SSG/LRR-omega-gamma transition turbulence model to further understand near-wall flow and wake characteristics. A qualitative analysis of the flow suggested that the swept rotor exhibited lower levels of blade wake interaction compared to the unswept geometry.

No abstract

No abstract

The current study is carried out to investigate complex near-wall flow effects like separation and cross-flow and their impact on UAV performance. Furthermore, the study proposes using the novel SSG/LRR-ω-γ model, which is a second-order closure, Reynolds stress transport-based transition turbulence model, that can help capture the near-wall flow observed in low Reynolds number flows. To prove the credibility of the model, it is validated against experimental data available for the DJI Phantom 3 propeller. The SSG/LRR-ω-γ model is then compared against other transition models as well as fully turbulent models and was found to show better performance when assessed on their ability to predict rotor performance characteristics as well as near-wall flow behavior.

No abstract