Nonlinear Responses of a Slender Wing With a Store

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Yuqian Xu ◽  
Dengqing Cao ◽  
Chonghui Shao ◽  
Huagang Lin
Keyword(s):  
Model Simulation ◽  
System Response ◽  
Horizontal Distance ◽  
Bifurcation Diagrams ◽  
Unsteady Aerodynamic ◽  
Model Based ◽  
Aerodynamic Model ◽  
Aeroelastic Model ◽  
Response Peak ◽  
Slender Wing

The aeroelastic characteristics of the slender wing with store have been studied for several years. However, the nonlinear aeroelastic behaviors of the wing-store system have not been understood thoroughly. In this paper, the nonlinear aeroelastic model of a slender wing with a store is constructed. In the model, the geometric structural nonlinearity of the wing, and the kinematic nonlinearities of the wing and the store are considered. Two unsteady aerodynamic models are both employed to determine the aerodynamic loads. One is the linear unsteady aerodynamic model based on Wagner function, and the other is the nonlinear ONERA aerodynamic model. Simulation results are given to show that for the cases of employing the linear unsteady aerodynamic model based on Wagner function, the bifurcation diagrams are very complex and change with the variations of store position. For the cases of using the nonlinear ONERA model, the bifurcation diagrams are very simple and insensitive to the variations of the store position. Additionally, with the decrease of store spanwise coordinate, the system bending oscillation equilibrium position is reduced to zero, and the maximum absolute value of the bending response peak is also decreased. With the increase of the horizontal distance between the wing elastic center and the store mass center, the system response peak is decreased. Moreover, it is found that for the systems with the linear unsteady aerodynamic model based on Wagner function, the obtained response peak is larger and the nonlinear critical velocity is smaller than those with the ONERA model.

Unsteady Aerodynamic Model Based on the Leading-Edge Stagnation Point

2016 ◽  
Vol 53 (6) ◽  
pp. 1626-1637 ◽  
Author(s):  
Vishvas S. Suryakumar ◽  
Yogesh Babbar ◽  
Thomas W. Strganac ◽  
Arun S. Mangalam
Keyword(s):  
Stagnation Point ◽  
Leading Edge ◽  
Unsteady Aerodynamic ◽  
Model Based ◽  
Aerodynamic Model

An Unsteady Aerodynamic Model based on the Leading-Edge Stagnation Point

2015 ◽  
Author(s):  
Vishvas S. Suryakumar ◽  
Yogesh Babbar ◽  
Thomas W. Strganac ◽  
Arun S. Mangalam
Keyword(s):  
Stagnation Point ◽  
Leading Edge ◽  
Unsteady Aerodynamic ◽  
Model Based ◽  
Aerodynamic Model

An investigation of lateral-directional departure behavior based on yawing–rolling coupled wind tunnel tests

2017 ◽  
Vol 232 (16) ◽  
pp. 2989-3000
Author(s):  
Lin Shen ◽  
Da Huang ◽  
Genxing Wu
Keyword(s):  
Wind Tunnel ◽  
Aerodynamic Characteristics ◽  
Flight Simulation ◽  
Wind Tunnel Tests ◽  
Unsteady Aerodynamic ◽  
Model Based ◽  
Aerodynamic Model ◽  
Data Prediction ◽  
Text Model ◽  
Departure Behavior

The traditional aerodynamic model based on the dynamic derivative tests and the [Formula: see text] model based on the yawing–rolling coupled motion tests are compared with respect to aerodynamic data, prediction of lateral-directional departure, and flight simulation. The study shows that the traditional model cannot fully reveal the unsteady aerodynamic characteristics and predict completely the departure behavior due to yaw–roll coupling. On the other hand, the [Formula: see text] model can reveal the departure behavior of an aircraft at some specific coupling ratios when the angle of attack reaches a critical value or more, using the aerodynamic data obtained from the yawing–rolling coupled wind tunnel tests. The comparison of flight simulation results shows that the lateral-directional departure is closely related to the coupling ratios, and for the investigated aircraft, the departure is mainly caused by the unsteady yawing and rolling moments at the coupling ratios showing unstable features.

A Time-Domain Fluid-Structure Interaction Analysis of Fan Blades

2008 ◽  
Author(s):  
Seung Ho Cho ◽  
Taehyoun Kim ◽  
Seung Jin Song
Keyword(s):  
Time Domain ◽  
Vortex Lattice ◽  
Interaction Analysis ◽  
Three Dimensional ◽  
Incoming Flow ◽  
Structure Interaction ◽  
Unsteady Aerodynamic ◽  
Aerodynamic Model ◽  
Blade Row ◽  
Fan Blade

This paper presents aerodynamic and aeromechanical analyses for an entire row of fan blades (i.e. tens of blades with a finite aspect ratio) subject to a uniform incoming flow. In this regard, a new unsteady three-dimensional vortex lattice model has been developed for multiple blades in discrete time domain. Using the new model, the characteristics of the unsteady aerodynamic forces on vibrating blades, including their temporal development, are examined. Also, the new aerodynamic model is applied to examine the aeromechanical behavior of fan blades by using a standard eigenvalue analysis. For this analysis, the fan blades have been modeled as three-dimensional plates, and, increasing the number of blades (or solidity) is predicted to destabilize the fan blade row.

scholarly journals Study on the High-Speed and Close of the UVA Cooperative Formation Controller Design

2018 ◽  
Vol 36 (2) ◽  
pp. 345-352
Author(s):  
Jialong Zhang ◽  
Jianguo Yan ◽  
Pu Zhang ◽  
Xiaoqiao Qi ◽  
Maolong Lü
Keyword(s):  
Dynamic Characteristic ◽  
High Speed ◽  
Controller Design ◽  
Design Method ◽  
Formation Flight ◽  
Unsteady Aerodynamic ◽  
Aerodynamic Model ◽  
Thrust Vector ◽  
The Stability ◽  
Rudder Angle

Aiming at the high-speed flight of the UAVs cooperative formation, when a single UAV has occurred, need to exit the formation flight and be close or super close to form of the formation quickly. A fast close cooperative formation controller design method is proposed to make up for low the fighting robustness, and be shortcomings of timeliness poorly and analyze the dynamic characteristic of UAV formation flight. Taking the external factors known into consideration, setting up for the longitude maneuver of nonlinear thrust vector and unsteady aerodynamic model, according to the formation velocity, flat tail rudder angle and thrust vector and pitch angle velocity for corresponding input commend signals for the controller to research the dynamic characteristic of UAV formation flight. Meanwhile, the formation flight distance error is the convergence to a fixed value, and the stability of the cooperative formation flight is good. The simulation of results show that the controller can effectively improve the speed of the close or super close to formation, and maintain the stability of the formation flight, which provides a method of the close or super close formation flight controller design.

scholarly journals Gust Response Analysis for Helicopter Rotors in the Hover and Forward Flights

2017 ◽  
Vol 2017 ◽  
pp. 1-20 ◽  
Author(s):  
Linpeng Wang ◽  
Yuting Dai ◽  
Chao Yang
Keyword(s):  
Shear Force ◽  
Thrust Force ◽  
Vertical Direction ◽  
Beam Theory ◽  
Response Analysis ◽  
Forward Flight ◽  
Helicopter Rotors ◽  
Aerodynamic Model ◽  
Aeroelastic Model ◽  
The Time Domain

Dynamic load due to gust for helicopter rotors directly affects the structural stress and flight performance. In case of gust, it may cause the loss of trust force or the increase of deflection for rotors. In current work, an effective coupled aeroelastic model based on a medium-deflection beam theory and a nonlinear unsteady aerodynamic model in the time domain were constructed. Three types of gust in vertical direction were added in the model. The dynamic response and structural load for helicopter rotors under three types of gust were calculated, respectively. Results indicated that when rotors suffer a gust in hover at downward direction, the thrust force on rotor disk would decrease significantly when the gust amplitude increases, which should be paid attention in the design. Among the three gust types with the same gust strength, the maximum instantaneous shear force due to impulse shape gust is the largest. When the rotors suffer a gust in a forward flight, the shear force at the root of rotors would increase with the gust strength first but then it decreases. More attention should be paid to the decrease of thrust force and the increase of structural load in a forward flight.

scholarly journals A DNN surrogate unsteady aerodynamic model for wind turbine loads calculations

2020 ◽  
Vol 1618 ◽  
pp. 052060
Author(s):  
Shreyas Ananthan ◽  
Ganesh Vijayakumar ◽  
Shashank Yellapantula
Keyword(s):  
Wind Turbine ◽  
Unsteady Aerodynamic ◽  
Aerodynamic Model

scholarly journals A Kite Simulator Based on Aerodynamic Model

2018 ◽  
Vol 246 ◽  
pp. 03042
Author(s):  
Lei Kangl ◽  
JianZhe Liang ◽  
CaiLing Wang
Keyword(s):  
Differential Equation ◽  
Ordinary Differential Equation ◽  
Wind Energy ◽  
Problem Solver ◽  
Model Based ◽  
Aerodynamic Model ◽  
Typical Trajectory

Kite simulator is important for training air borne wind energy controllers. A kite model based on aerodynamics and ordinary differential equation has been proposed to calculate kites’ trajectory in the air. A constant problem solver has also been developed to study the system’s stability and cross validate the simulators behaviour. Elementary evaluation shows a typical trajectory of a kite and verifies the system’s stability.

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