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.

Rotor blade-vortex interaction

Abstract: The vortex lattice method has been extended to a single bladed rotor operating at high advance ratios and encountering a free vortex from a fixed wing upstream of the rotor. The predicted unsteady load distributions on the model rotor blade are generally in agreement with the experimental results. This method has also been extended to full scale rotor flight cases in which vortex induced loads near the tip of a rotor blade were indicated. Using conformal transformation methods an exact analysis of the effects of thickness on the lift due to a two dimensional wing vortex interaction is presented.

Beyond Quasi-Analytical Methods for Preliminary Structural Sizing and Weight Estimation of Lifting Surfaces

Abstract: This paper presents the development and implementation of a tool for wing structural sizing and aeroelastic optimization in early design steps, where the amount of available data about the wing structure is not enough to allow high fidelity finite element analysis and optimization. The proposed tool consists of two levels. The first level is a quasianalytical method for wing structural weight estimation and initially sizing of the wing box structure. The second level is an aeroelastic tool that uses a vortex lattice method and a finite beam element to compute the stress distribution in the wing box structure. The Newton-Krylov method is used to solve the coupled system. The coupled adjoint sensitivity analysis method is used to compute the sensitivity of any function of interest with respect to the design variables. The tool was used for a series of wing aeroelastic optimizations to minimize the wing weight with a series of constraints on the wing structural failure modes and aileron effectiveness. Another series of optimizations is also used to find the wing jig shape for a predefined cruise shape. The outputs of the optimizations showed that the wing box weight varies quadratically with the required value for the aileron effectiveness.

Calculation of wing response to gusts and blast waves with vortex lift effect

Abstract: A numerical study of the response of aircraft wings to atmospheric gusts and to nuclear explosions when flying at subsonic speeds is presented. The method is based upon unsteady quasi-vortex lattice method, unsteady suction analogy and Pade approximant. The calculated results, showing vortex lag effect, yield reasonable agreement with experimental data for incremental lift on wings in gust penetration and due to nuclear blast waves.

Stability and Flying Qualities of an Unmanned Airplane using Vortex Lattice Method

Abstract: CLq, CMq = variation of lift and pitching moment coefficients with pitch rate CL , CD , CM = lift, drag, and pitching moment slopes CL , CM = variation of lift and pitching moment coefficients with rate of change of angle of attack CL , CM = variation of lift and pitching moment coefficients with elevator deflection C‘p, Cnp, CYp = variation of rolling, yawing, and side force coefficients with roll rate C‘r, Cnr, CYr = variation of rolling, yawing, and side force coefficients with yaw rate C‘ , Cn , CY = variation of rolling, yawing, and side force coefficients with sideslip angle C‘ r, Cn r, CY r = variation of rolling, yawing, and side force coefficients with rudder angle C‘ a, Cn a, CY a = variation of rolling, yawing, and side force coefficients with aileron angle c = mean aerodynamic chord p, q, r = roll, pitch, and yaw rate T = period t1=2, N1=2 = time and number of cycles to half-amplitude u, w = longitudinal and vertical components of velocity = angle of attack = sideslip angle e, r, a = elevator, rudder, and aileron deflection = damping ratio , = pitch and bank angle = eigenvalue !n = undamped natural frequency

Preliminary Take-Off Analysis and Simulation of PrandtlPlane Commercial Aircraft

Abstract: The present paper deals with the take-off performance analysis of PrandtlPlane aircraft. The PrandtlPlane is a Box-Wing configuration based on Prandtl’s “Best Wing System” concept, which minimizes the induced drag once wingspan and lift are given. The take-off dynamics is simulated implementing the non-linear equations of motion in a numerical tool, which adopts a Vortex Lattice Method solver to evaluate the aerodynamics characteristics taking also ground effects into account. The take-off analysis is performed for both a PrandtlPlane and a reference monoplane, with the aim of comparing the performance of the two different architectures. The preliminary results show the potential advantages of the PrandtlPlane, such as runway length reduction and improved passenger comfort.