scholarly journals Computational Study of a Transverse Rotor Aircraft in Hover Using the Unsteady Vortex Lattice Method

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Juan D. Colmenares ◽  
Omar D. López ◽  
Sergio Preidikman
Keyword(s):  
Vortex Lattice ◽  
Computational Study ◽  
Pitching Moment ◽  
Considerable Influence ◽  
Lattice Method ◽  
Vortex Lattice Method ◽  
Geometric Configurations ◽  
Hover Flight ◽  
High Reynolds ◽  
The Stability

This paper presents the simulation of a two-rotor aircraft in different geometric configurations during hover flight. The analysis was performed using an implementation of the unsteady vortex-lattice method (UVLM). A description of the UVLM is presented as well as the techniques used to enhance the stability of results for rotors in hover flight. The model is validated for an isolated rotor in hover, comparing numerical results to experimental data (high-Reynolds, low-Mach conditions). Results show that an exclusion of the root vortex generates a more stable wake, without affecting results. Results for the two-rotor aircraft show an important influence of the number of blades on the vertical thrust. Furthermore, the geometric configuration has a considerable influence on the pitching moment.

An Analytic and Experimental Investigation of the Aerodynamic Performance Enhancements of Multiple Winglet Configurations

2005 ◽  
Author(s):  
D. S. Miklosovic ◽  
P. M. Bookey
Keyword(s):  
Aspect Ratio ◽  
Vortex Lattice ◽  
Dihedral Angles ◽  
Pitching Moment ◽  
Lattice Method ◽  
Vortex Lattice Method ◽  
Moment Coefficient ◽  
Effectiveness And Efficiency ◽  
Low Speed Wind Tunnel ◽  
Experimental Effort

An experimental effort was undertaken to assess the effectiveness and efficiency of three winglets mounted chordwise to the tip of a rectangular wing (NACA 0018 section). The winglets, with an aspect ratio of 3.6, were mounted on a half-span wing having an aspect ratio of 3.1. Twenty configurations of varying dihedral arrangements were analyzed with a vortex lattice method and tested in a low-speed wind tunnel at a Reynolds number of 600,000. In general, the arrangements involving high dihedral angles had lower performance increments, due to lower lift and higher interference drag. More specifically, the results showed that the winglets placed at 60, 45, and 30 degrees, respectively, produced nominal 4% higher lift and 46% lower drag. The most dramatic findings from this study show that positioning the winglet dihedral angles had the result of adjusting the point of maximum L/D and the magnitude of the pitching moment coefficient. These observations suggest that multiple winglet dihedral changes affect the lift, drag, and pitching moment in such a way that they are feasible for use as actively-controlled surfaces to improve the performance of aircraft at various flight conditions and to “tune” the longitudinal stability characteristics of the wing.

Modified Unsteady Vortex-Lattice Method to Study Flapping Wings in Hover Flight

AIAA Journal ◽  
2013 ◽  
Vol 51 (11) ◽  
pp. 2628-2642 ◽  
Author(s):  
Bruno A. Roccia ◽  
Sergio Preidikman ◽  
Julio C. Massa ◽  
Dean T. Mook
Keyword(s):  
Vortex Lattice ◽  
Flapping Wings ◽  
Lattice Method ◽  
Vortex Lattice Method ◽  
Hover Flight

scholarly journals Nonlinear Aeroelastic Simulations and Stability Analysis of the Pazy Wing Aeroelastic Benchmark

Aerospace ◽  
2021 ◽  
Vol 8 (10) ◽  
pp. 308
Author(s):  
Jonathan Hilger ◽  
Markus Raimund Ritter
Keyword(s):  
Stability Analysis ◽  
Wind Tunnel ◽  
Vortex Lattice ◽  
Structural Model ◽  
State Space Model ◽  
Lattice Method ◽  
Vortex Lattice Method ◽  
Aeroelastic Simulations ◽  
The Stability ◽  
German Aerospace

The Pazy wing aeroelastic benchmark is a highly flexible wind tunnel model investigated in the Large Deflection Working Group as part of the Third Aeroelastic Prediction Workshop. Due to the design of the model, very large elastic deformations in the order of 50% span are generated at highest dynamic pressures and angles of attack in the wind tunnel. This paper presents static coupling simulations and stability analyses for selected onflow velocities and angles of attack. Therefore, an aeroelastic solver developed at the German Aerospace Center (DLR) is used for static coupling simulations, which couples a vortex lattice method with the commercial finite element solver MSC Nastran. For the stability analysis, a linearised aerodynamic model is derived analytically from the unsteady vortex lattice method and integrated with a modal structural model into a monolithic aeroelastic discrete-time state-space model. The aeroelastic stability is then determined by calculating the eigenvalues of the system’s dynamics matrix. It is shown that the stability of the wing in terms of flutter changes significantly with increasing deflection and is heavily influenced by the change in modal properties, i.e., structural eigenvalues and eigenvectors.

Generalized vortex lattice method for planar supersonic flow

AIAA Journal ◽  
1997 ◽  
Vol 35 ◽  
pp. 1230-1233
Author(s):  
Paulo A. O. Soviero ◽  
Hugo B. Resende
Keyword(s):  
Supersonic Flow ◽  
Vortex Lattice ◽  
Lattice Method ◽  
Vortex Lattice Method

scholarly journals Static Aeroelastic Characteristics of Morphing Trailing-Edge Wing Using Geometrically Exact Vortex Lattice Method

2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
Sen Mao ◽  
Changchuan Xie ◽  
Lan Yang ◽  
Chao Yang
Keyword(s):  
Vortex Lattice ◽  
Deflection Angle ◽  
Aircraft Design ◽  
Analysis Method ◽  
Lattice Method ◽  
Trailing Edge ◽  
Vortex Lattice Method ◽  
Analysis And Design ◽  
Aeroelastic Analysis ◽  
Typical Model

A morphing trailing-edge (TE) wing is an important morphing mode in aircraft design. In order to explore the static aeroelastic characteristics of a morphing TE wing, an efficient and feasible method for static aeroelastic analysis has been developed in this paper. A geometrically exact vortex lattice method (VLM) is applied to calculate the aerodynamic forces. Firstly, a typical model of a morphing TE wing is chosen and built which has an active morphing trailing edge driven by a piezoelectric patch. Then, the paper carries out the static aeroelastic analysis of the morphing TE wing and corresponding simulations were carried out. Finally, the analysis results are compared with those of a traditional wing with a rigid trailing edge using the traditional linearized VLM. The results indicate that the geometrically exact VLM can better describe the aerodynamic nonlinearity of a morphing TE wing in consideration of geometrical deformation in aeroelastic analysis. Moreover, out of consideration of the angle of attack, the deflection angle of the trailing edge, among others, the wing system does not show divergence but bifurcation. Consequently, the aeroelastic analysis method proposed in this paper is more applicable to the analysis and design of a morphing TE wing.

scholarly journals Analysis of wing flap configurations by a nonplanar vortex lattice method

1988 ◽  
Vol 25 (2) ◽  
pp. 97-98 ◽  
Author(s):  
B. Rajeswari ◽  
H. N. V. Dutt
Keyword(s):  
Vortex Lattice ◽  
Lattice Method ◽  
Vortex Lattice Method
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