Vortex lattice method

About: Vortex lattice method is a research topic. Over the lifetime, 779 publications have been published within this topic receiving 9242 citations.

Design of fixed wing micro air vehicles

Abstract: The paper describes the methodology and computational design strategies used to develop a series of fixed wing micro air vehicles (MAVs) at the Ghent University. The emphasis of the research is to find an optimal MAV-platform that is bound to geometrical constraints but superior in its performance. This requires a multidisciplinary design optimisation but the challenges are mainly of aerodynamic nature. Key areas are endurance, stability, controllability, manoeuvrability and component integration. The highly three-dimensional low Reynolds number flow, the lack of experimental databases and analytical or empirical models of MAV-aerodynamics required fundamental research of the phenomena. This includes the use of a vortex lattice method, three-dimensional CFD-computations and a numerical propeller optimisation method to derive the forces and their derivatives of the MAV and propeller for performance and stability-related optimisation studies. The design method leads to a simple, stable and robust flying wing MAV-platform that has the agility of a fighter airplane. A prototype, the UGMAV25, was constructed and flight tests were performed. The capabilities of the MAV were tested in a series of successful flight manoeuvres. The UGMAV15, a MAV with a span of 15cm, is also developed to test flight-qualities and endurance at this small scale. With the current battery technology, a flight-time of at least one hour is expected.

Development of a Solar Electric Powered UAV for Long Endurance Flight

Abstract: The development of a solar electric powered UAV (Unmanned Aerial Vehicle) is systematically introduced in this paper. The purpose of the project is to prove the feasibility of some crucial engineering techniques for future full-scale high altitude solar powered UAVs. The solar electric powered UAV adopted a normal configuration of a sailplane with wing of high aspect ratio, slender fuselage, and a tail boom. Aerodynamic geometry and longitudinal trim and stability performances were designed via lifting line theory, and verified using AVL code based on vortex lattice method. Composite and balsa combined structure was designed for the purpose of light weight and rigidness. Carbon-balsa-carbon laminated structure was used for the D-box of the wing and fuselage, which gave adequate strength and rigidness to the wing to carry solar array. Fragile photovoltaic cells were bended and mounted onto the surface of the wing, and would be working cooperatively with lithium-polymer secondary battery to drive the propulsion system. A miniature onboard power management device was developed to adjust and monitor the output power of PV cells and secondary battery. A set of ground tests and flight tests were carried out, the aerodynamic performance, power supply ability of solar array, function and efficiency of the power management device were all demonstrated and validated. The test results showed that the efficiency of the power management device was greater than 85%, the input power requirement for straight and level flight was less than 80 W, and the minimum solar radiation sufficient to support straight and level flight solely was 650 W/m 2 . All of the design objectives had been achieved.

Continuous-Time State-Space Unsteady Aerodynamic Modeling for Efficient Loads Analysis

Abstract: The present paper proposes a continuous-time state-space formulation of the unsteady vortex lattice method, which is derived through a discretization of the governing advection equation for transpo...