Investigation of the Flow Around Symmetric and Cambered Airfoils Interacting with a Gust at Low Reynolds Numbers*

Understanding the interaction of small Unmanned Aircraft Systems (sUAS) with vertical gusts is an important step in their development and use. Common methods for gust generation are highly transient and tend to create short-lived gust interactions. The Actuated Recirculating Gust Generator for sUAS Studies (ARGGUS) was developed to study the interaction of wings with vertical gusts of controllable length and magnitudes up to 30% of the free stream velocity at low Reynolds numbers. This work focuses on the flow around three airfoils entering and exiting vertical gusts created by the ARGGUS. Full-span NACA 0012, Eppler 387, and SD 5060 airfoils were held at static angles of attack during encounters with gusts of 20% and 30% of the free stream velocity at a Reynolds number of 12x10³. The wings also interacted with a gust of 20% of the free stream at a Reynolds number of 54.4x10³. Particle Image Velocimetry was used to capture the flow field around the airfoils. The flow around the NACA 0012 was compared to similar experiments and simulations along with the cambered wings. This allowed for an investigation into the impacts of camber during a gust encounter. Testing the Eppler and SD airfoil also allowed for analyzing gust effects on airfoils specifically designed for low Reynolds number operation.