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.

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.

scholarly journals Typhoon: A vortex-lattice code for assessing dynamic stability characteristics of hydrofoil crafts

2021 ◽  
pp. 1-18
Author(s):  
Alec Bagué ◽  
Joris Degroote ◽  
Toon Demeester ◽  
Evert Lataire
Keyword(s):  
Stability Analysis ◽  
Dynamic Stability ◽  
Vortex Lattice ◽  
Theoretical Explanation ◽  
Surface Boundary ◽  
Lattice Method ◽  
Vortex Lattice Method ◽  
Lattice Codes ◽  
Cheap Alternative ◽  
The Difference

In this paper an open-source implementation of the vortex-lattice method to perform a dynamic stability analysis for hydrofoil crafts is discussed. The difference with existing vortex-lattice codes is the addition of a free-surface boundary condition which is needed to analyse surface piercing foils. This code, called Typhoon, can be used to perform a dynamic stability analysis (DSA) on hydrofoil vessels. The goal of this code is to have an easy-to-use and cheap alternative to compare different designs in early design stages. This paper gives a brief background to all the concepts used, followed by a short theoretical explanation of the vortex-lattice method. The second part of this paper focuses on a practical example of how this code can be used on an example.

Comparison of Tacking and Wearing Performance Between a Japanese Traditional Square Rig and a Chinese Lug Rig

2005 ◽  
Author(s):  
Yutaka Masuyama ◽  
Akira Sakurai ◽  
Toichi Fukas ◽  
Kazunori Aoki
Keyword(s):  
Wind Tunnel ◽  
Vortex Lattice ◽  
Aerodynamic Performance ◽  
Measured Data ◽  
The Other ◽  
Aerodynamic Forces ◽  
Lattice Method ◽  
Wind Tunnel Tests ◽  
Vortex Lattice Method ◽  
Force Variation

Aerodynamic performance of a Japanese traditional square rig, “Bezai-ho”, and a Chinese lug rig, “Shinshi-bo” in Japanese, were studied by means of wind tunnel tests, sea trials and numerical calculations. Sail forces and sail shapes were measured in the wind tunnel tests. A sail dynamometer boat Fujin was employed for the sea trials, by which aerodynamic forces acting on sail, sail shapes, and sailing conditions of the boat can be measured at the same time. Using the measured sail shapes, sail forces are calculated by means of a vortex lattice method. Differences of sail performance of the above mentioned two types of rig were clarified in the wind tunnel tests and sea trials. The calculated sail performance shows good agreements with the measured data in upwind condition. Dynamic sail performance of the two types of rig during tacking and wearing operations was also clarified in the sea trials using the boat Fujin. Details of sail force variation in time during maneuvering can be investigated by the sail dynamometer system. For the “Bezai-ho,” the backward force acting on sail when the boat changes tacks (wind over the bow) was investigated. At this moment, the square sail falls into a “caught aback” situation, which makes the tacking operation difficult. On the other hand, “Shinshi-bo” showed good steady performance similar to that of the modern marconi rig, and good tacking performance. Obtained results of steady and dynamic sail performance in this paper provide useful information for sail trimming and maneuvering of boats equipped with the western square rigs and modern lug rig introduced by H.G. Hasler.

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.

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