A Highly Efficient Aeroelastic Analysis Method Based on External Aerodynamic Force and Strip Theory

2018 ◽  
Author(s):  
Qi Yan ◽  
Zhiqiang Wan
Keyword(s):  
Aerodynamic Force ◽  
Analysis Method ◽  
Highly Efficient ◽  
Aeroelastic Analysis ◽  
Strip Theory

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.

Tacking in the Wind Tunnel

2009 ◽  
Author(s):  
Frederik C. Gerhardt ◽  
David Le Pelley ◽  
Richard G. J. Flay ◽  
Peter Richards
Keyword(s):  
Wind Tunnel ◽  
Aerodynamic Force ◽  
Three Dimensional ◽  
Added Mass ◽  
Mass Moment ◽  
Strip Theory ◽  
Dynamic Velocity ◽  
Order Of Magnitude ◽  
Velocity Prediction ◽  
Unsteady Effects

In recent years a number of Dynamic Velocity Prediction Programs (DVPPs), which allow studying the behaviour of a yacht while tacking, have been developed. The aerodynamic models used in DVPPs usually suffer from a lack of available data on the behaviour of the sail forces at very low apparent wind angles where the sails are flogging. In this paper measured aerodynamic force and moment coefficients for apparent wind angles between 0° and 30° are presented. Tests were carried out in the University of Auckland’s Twisted Flow Wind Tunnel in a quasi-steady manner for stepwise changes of the apparent wind angle. Test results for different tacking scenarios (genoa flogging or backed) are presented and discussed and it is found that a backed headsail does not necessarily produce more drag than a flogging headsail but increases the beneficial yawing moment significantly. The quasisteady approach used in the wind tunnel tests does not account for unsteady effects like the aerodynamic inertia in roll due to the “added mass” of the sails. In the second part of paper the added mass moment of inertia of a mainsail is estimated by “strip theory” and found to be significant. Using expressions from the literature the order of magnitude of three-dimensional effects neglected in strip theory is then assessed. To further quantify the added inertia experiments with a mainsail model were carried out. Results from those tests are presented at the end of the paper and indicate that the added inertia is about 76 % of what strip theory predicts.

Efficient Aeroelastic Analysis Method Including Inverse Design for Body Effects

2009 ◽  
Vol 46 (6) ◽  
pp. 2164-2169
Author(s):  
Seung-Jun Lee ◽  
Dong-Kyun Im ◽  
Myung-Koo Kang ◽  
In Lee ◽  
Jang-Hyuk Kwon
Keyword(s):  
Inverse Design ◽  
Analysis Method ◽  
Aeroelastic Analysis

A Unified Approach for the Aeroelastic Analysis by Elimination of Frequency Dependence of Aerodynamic Force

2012 ◽  
Vol 18 (24) ◽  
pp. 579-584
Author(s):  
Kilje Jung ◽  
Hae Sung Lee ◽  
Ho-Kyung Kim ◽  
Hong Yun Hwa
Keyword(s):  
Frequency Dependence ◽  
Aerodynamic Force ◽  
Unified Approach ◽  
Aeroelastic Analysis

A Robust Aerodynamic Optimization Design for Airfoil Based on Interval Uncertainty Analysis Method

2019 ◽  
Author(s):  
Xin Song ◽  
Guannan Zheng ◽  
Guowei Yang
Keyword(s):  
Robust Optimization ◽  
Interval Analysis ◽  
Optimization Design ◽  
Aerodynamic Force ◽  
Interval Uncertainty ◽  
Upper And Lower Bounds ◽  
Analysis Method ◽  
Geometric Uncertainties ◽  
Interval Analysis Method ◽  
Robust Optimization Design

Abstract Uncertainties will make aircraft deviate from the designed condition, resulting in the decrease in aerodynamic performance and even destruction. This paper presents a fast nonlinear interval analysis method considering geometric uncertainties. DFFD method is used to parameterize the airfoil shape, and the Kriging model for aerodynamic force and uncertainty variables is optimized by PSO algorithm to find the upper and lower bounds of the objective interval. The effects of geometric uncertainties on NACA0012 airfoil are analyzed using the above method. And then, a robust optimization design method is established based on the interval analysis method. FFD method is used to produce the deterministic design variables and the order relation of interval number is employed to transform the uncertain optimization to deterministic multi-objective optimization which is solved by MOPSO based on Pareto entropy. The robust optimization design is implemented for the symmetrical airfoil with the drag objective under geometric uncertainties and thickness constraint, and the results are compared with the deterministic optimization to validate the effectiveness of the developed method.

scholarly journals 0682 A Novel, Highly Efficient REM Sleep without Atonia Visual Analysis Method for REM Sleep Behavior Disorder Diagnosis

SLEEP ◽  
2018 ◽  
Vol 41 (suppl_1) ◽  
pp. A253-A253
Author(s):  
J C Feemster ◽  
S J McCarter ◽  
P C Timm ◽  
L N Teigen ◽  
E K St. Louis
Keyword(s):  
Rem Sleep ◽  
Visual Analysis ◽  
Rem Sleep Behavior Disorder ◽  
Behavior Disorder ◽  
Analysis Method ◽  
Sleep Behavior ◽  
Highly Efficient ◽  
Rem Sleep Without Atonia

FLUID-STRUCTURE INTERACTION ANALYSIS OF HINGELESS ROTOR BLADES IN HOVER CONSIDERING WAKE EFFECTS

2010 ◽  
Vol 24 (13) ◽  
pp. 1475-1478 ◽  
Author(s):  
SEUNG-JAE YOO ◽  
MIN-SOO JEONG ◽  
IN LEE
Keyword(s):  
Interaction Analysis ◽  
Damping Ratio ◽  
Three Dimensional ◽  
Beam Theory ◽  
Rotor Blades ◽  
Aeroelastic Stability ◽  
Lattice Method ◽  
Aeroelastic Analysis ◽  
Strip Theory ◽  
Wake Effects

Aeroelastic analysis of hingeless rotor blades in hover was performed. Large deflection beam theory was applied to analyze blade motions with effects of geometric structural nonlinearity. Aerodynamic loads for aeroelastic analysis were calculated through a three-dimensional aerodynamic model which is based on the unsteady vortex lattice method. Wake geometry was described using a time-marching free-wake method. Lead-lag damping ratio and frequency were calculated to evaluate aeroelastic stability of hingeless rotor system. Numerical results of aeroelastic analysis for hingeless rotor blades were presented and compared with results based on experimental data and two-dimensional quasi-steady strip theory in which uniform inflow model was used. It was shown that wakes significantly affect the steady-state deflections and aeroelastic stability.

Analysis of Rotor Blade Aeroelastic Deformation Utilizing the Uncoupled Static Aeroelastic Analysis Method

2022 ◽  
Author(s):  
Francis R. Phillips ◽  
Trent D. White ◽  
Allen Davis ◽  
Darren J. Hartl
Keyword(s):  
Rotor Blade ◽  
Analysis Method ◽  
Aeroelastic Analysis
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