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.

A Comparison of Methods for the Analysis of Wing-Tail Interaction Flutter

Abstract: Results of an analytical investigation of the aeroelastic stability of variable sweep aircraft, specifically with respect to wing-tail interaction flutter, are presented. Three aerodynamic representations are employed: 1) modified two-dimensional strip theory containing no wingtail aerodynamic interaction, 2) vortex lattice theory containing aerodynamic interaction of wing on tail only, and 3) subsonic kernel function theory containing a complete evaluation of wing-tail aerodynamic interaction. The capability of the interaction methods is established by an application to an experimental flutter model where wing-tail aerodynamic interaction is known to be of importance. The aerodynamic methods are then applied to a particular high performance variable sweep aircraft. The basic flutter mechanisms for this hypothetical aircraft are generated by wing-fuselage mechanical interaction and are predicted by wing aerodynamics alone. Component aerodynamics on wing and tail without interaction do not predict the mechanism. Aerodynamic interaction causes the reappearance of flutter at a velocity 30% lower than generated by the wing alone.

Numerical simulation of rolling up of leading/trailing-edge vortex sheets for slender wings

Abstract: In present paper we compute the rolling up of leading/trailing-edge vortex sheets and their interaction for delta and double-delta wings, using a simple two-dimensional discrete vortex model. The numerical results show that a trailing-edge vortex, which has an opposite sign of circulation of the leading-edge vortices, can be rolled up for both delta and double-delta wings and that two separated leading edge vortices, inboard and outboard, can be formed over a double-delta wing surface. The two vortices are separated from each other at small angles of attack, and the inboard vortex merges with the outboard one when the angles of attack are increased. The numerical results are in good agreement with Hummers experiments. According to the rolled-up leading-edge vortices and Donaldson's criterion, the numbers, positions, and signs and strength of rolled up trailing-edge vortices may be predicted. A simplified method that may improve the predicting of downwash field is suggested.

Analysis of aerodynamic characteristics using the vortex lattice method on twin tail boom unmanned aircraft

Abstract: This study focuses on analysis the aerodynamic characteristics of the LSU 05-NG aircraft in a relatively shorter time with sufficient results to provide an overview of aircraft characteristics. The method used is the Vortex Lattice Method (VLM) on XFLR5 software. VLM models an aircraft surface into infinite number of vortices to calculate lift curve slope, induced drag and force distribution. In this study, VLM was used to calculate aerodynamic parameters which include CL, CD, CM, CL with respect to CD, and L/D. The results showed that VLM can provide good results for the prediction of the lift coefficient. As for the drag coefficient, VLM used the assumption that fluid flow is inviscid so only induced drag is calculated. This also impacted the results of L/D analysis using VLM. Simulation results for the value of L/D results showed that the VLM simulation on XFLR5 has a higher magnitude than the results of the simulation with CFX.

Unsteady Aerodynamic Vortex Lattice of Moving Aircraft

Abstract: It is aim of this thesis to develop a potential ow solver for unsteady aerodynamics in MATLAB environment. In order to achieve this target a vortex lattice method based has been developed. The vali ...