Numerical Simulation of Air Jet Attachment to Convex Walls and Application to UAV

Abstract

In this paper, we present a numerical study of the wall jet flow over a convex surface, viz. the Coanda wall jet, and its application to a conceptual Unmanned Aerial Vehicle (UAV) design which uses the Coanda effect as a basis of lift production. This configuration is important in a way that it considers the Coanda wall jet over a smooth convex wall with non-constant curvature, in contrast to most of the previous situations where only constant curvature walls were considered e.g. the Coanda wall jet over circular cylinder. To enable the mathematical representation of this complex geometrical configuration, we propose a form of a parametric representation of the conceptual geometry, based on Bernstein polynomials, which is universal in character and spans a complete design space. It is shown how dynamically changing the flow picture enables smooth change of net forces on the body. Capability to control the direction of the net force is shown to be useful for maneuvering the UAV. All simulations are done using an open-source finite-volume computational fluid dynamics code based on Reynolds-averaged Navier-Stokes equations. Turbulence is accounted for using the k −ω Shear Stress Transport model.