A LOW-NOISE AIRFOIL FOR LOW REYNOLDS APPLICATIONS: A MULTI-FIDELITY OPTIMIZATION

Automotive fans, small wind turbines, and manned and unmanned aerial vehicles (MAVs/UAVs) are just a few of the examples in which noise generated by the flow interaction with the aerodynamic surfaces is a major concern. The current work shows the potential of a new airfoil shape to minimize noise generation, maintaining high lift-to-drag ratio in the low-Re regime (Re ≤2e5). The investigation is carried out by means of a multi-fidelity approach: a low-fidelity semi-empirical model is exploited for evaluating the sound pressure level (SPL). The fast evaluation of the low-cost function enables the computation of a large range of possible profiles, and accuracy is added to the low-fidelity response surface with high-fidelity CFD data. The constraint of maintaining a pre-defined range of the lift coefficient and lift-to-drag ratio ensures the possibility of using this profile in usual design procedures.