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Jae-hung Han - One of the best experts on this subject based on the ideXlab platform.
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Dynamic Stability of Flapping-Wing Micro Air Vehicles With Unsteady Aerodynamic Model
Volume 1A Symposia: Keynotes; Advances in Numerical Modeling for Turbomachinery Flow Optimization; Fluid Machinery; Industrial and Environmental Appli, 2017Co-Authors: Jae-hung Han, Anh Tuan NguyenAbstract:In this paper, we introduce a numerical approach based on an unsteady Aerodynamic Model to study the dynamic stability of insect-like flapping-wing micro air vehicles (FWMAVs). Trimmed free flight of FWMAVs is simulated by a framework that couples the unsteady potential-based Aerodynamic Model and a multibody dynamics code. Flight dynamic modal structures are obtained by a linearization method. This paper also briefly presents the applications of the abovementioned approach to study several problems associated with the flight dynamic stability of FWMAVs, such as the effects of body Aerodynamics and wing flexibility, as well as the ground effect.
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an Aerodynamic Model for insect flapping wings in forward flight
Bioinspiration & Biomimetics, 2017Co-Authors: Jongseob Han, Jo Won Chang, Jae-hung HanAbstract:This paper proposes a semi-empirical quasi-steady Aerodynamic Model of a flapping wing in forward flight. A total of 147 individual cases, which consisted of advance ratios J of 0 (hovering), 0.125, 0.25, 0.5, 0.75, 1 and ∞, and angles of attack α of −5 to 95° at intervals of 5°, were examined to extract the Aerodynamic coefficients. The Polhamus leading-edge suction analogy and power functions were then employed to establish the Aerodynamic Model. In order to preserve the existing level of simplicity, K P and K V, the correction factors of the potential and vortex force Models, were rebuilt as functions of J and α. The estimations were nearly identical to direct force/moment measurements which were obtained from both artificial and practical wingbeat motions of a hawkmoth. The Model effectively compensated for the influences of J, particularly showing outstanding moment estimation capabilities. With this Model, we found that using a lower value of α during the downstroke would be an effective strategy for generating adequate lift in forward flight. The rotational force and moment components had noticeable portions generating both thrust and counteract pitching moment during pronation. In the upstroke phase, the added mass component played a major role in generating thrust in forward flight. The proposed Model would be useful for a better understanding of flight stability, control, and the dynamic characteristics of flapping wing flyers, and for designing flapping-wing micro air vehicles.
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Aeroelastic analysis of wind turbine blades based on modified strip theory
Journal of Wind Engineering and Industrial Aerodynamics, 2012Co-Authors: Jong-won Lee, Junseong Lee, Jae-hung Han, Hyung-ki ShinAbstract:Abstract This study investigates the performance and aeroelastic characteristics of wind turbine blades based on flexible multibody dynamics, a new Aerodynamic Model, and the fluid–structure interaction approach. A new Aerodynamic Model is proposed based on modified strip theory (MST). MST was established for flapping wing Aerodynamic Models and considers a high relative angle of attack and dynamic stall effects. A simulated wind turbine blade was Modeled using multibody dynamics software (MSC.ADAMS), where the flexible parts can be included by importing a finite element Model built in finite element analysis software (ANSYS). The aeroelastic responses of the blade were obtained by coupling these Aerodynamic and structural Models. The proposed aeroelastic analysis method was validated using the predicted performance of the NREL 5MW Model reported in the literature.
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improved Aerodynamic Model for efficient analysis of flapping wing flight
AIAA Journal, 2011Co-Authors: Dae-kwan Kim, Junseong Lee, Jae-hung HanAbstract:This work was supported by a Korea Research Foundation Grant funded by the Korean Government (MOEHRD) (KRF-2007-313- D00122). The second author would like to thank the Brain Korea 21 Project in 2010. The authors would like to thank James D. DeLaurier of the University of Toronto and M. Okamoto of the Akita National College of Technology for their gracious support for this study. The authors also thank anonymous reviewers and the Editor for their valuable comments and suggestions.
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An aeroelastic analysis of a flexible flapping wing using modified strip theory
Active and Passive Smart Structures and Integrated Systems 2008, 2008Co-Authors: Dae-kwan Kim, Junseong Lee, Jin-young Lee, Jae-hung HanAbstract:The present study proposed a coupling method for the fluid-structural interaction analysis of a flexible flapping wing. An efficient numerical Aerodynamic Model was suggested, which was based on the modified strip theory and further improved to take into account a high relative angle of attack and dynamic stall effects induced by pitching and plunging motions. The Aerodynamic Model was verified with experimental data of rigid wings. A reduced structural Model of a rectangular flapping wing was also established by using flexible multibody dynamics, so as to consider large flapping motions and local elastic deformations. Then, the aeroelastic analysis method was developed by coupling these Aerodynamic and structural modules. To measure the Aerodynamic forces of the rectangular flapping wing, static and dynamic tests were performed in a low speed wind-tunnel for various flapping pitch angles, flapping frequencies and the airspeeds. Finally, the Aerodynamic forces predicted by the aeroelastic analysis method showed good agreement with the experimental data of the rectangular flapping wing.
M. Uddin - One of the best experts on this subject based on the ideXlab platform.
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High Fidelity Quasi Steady-State Aerodynamic Model Effects on Race Vehicle Performance Predictions Using Multi-Body Simulation
Vehicle System Dynamics, 2016Co-Authors: J. A. Mohrfeld-halterman, M. UddinAbstract:ABSTRACTWe described in this paper the development of a high fidelity vehicle Aerodynamic Model to fit wind tunnel test data over a wide range of vehicle orientations. We also present a comparison between the effects of this proposed Model and a conventional quasi steady-state Aerodynamic Model on race vehicle simulation results. This is done by implementing both of these Models independently in multi-body quasi steady-state simulations to determine the effects of the high fidelity Aerodynamic Model on race vehicle performance metrics. The quasi steady state vehicle simulation is developed with a multi-body NASCAR Truck vehicle Model, and simulations are conducted for three different types of NASCAR race tracks, a short track, a one and a half mile intermediate track, and a higher speed, two mile intermediate race track. For each track simulation, the effects of the Aerodynamic Model on handling, maximum corner speed, and drive force metrics are analysed. The accuracy of the high-fidelity Model is shown t...
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Quasi steady-state Aerodynamic Model development for race vehicle simulations
Vehicle System Dynamics, 2016Co-Authors: J. A. Mohrfeld-halterman, M. UddinAbstract:Presented in this paper is a procedure to develop a high fidelity quasi steady-state Aerodynamic Model for use in race car vehicle dynamic simulations. Developed to fit quasi steady-state wind tunnel data, the Aerodynamic Model is regressed against three independent variables: front ground clearance, rear ride height, and yaw angle. An initial dual range Model is presented and then further refined to reduce the Model complexity while maintaining a high level of predictive accuracy. The Model complexity reduction decreases the required amount of wind tunnel data thereby reducing wind tunnel testing time and cost. The quasi steady-state Aerodynamic Model for the pitch moment degree of freedom is systematically developed in this paper. This same procedure can be extended to the other five Aerodynamic degrees of freedom to develop a complete six degree of freedom quasi steady-state Aerodynamic Model for any vehicle.
Roeland De Breuker - One of the best experts on this subject based on the ideXlab platform.
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The effects of a full-aircraft Aerodynamic Model on the design of a tailored composite wing
CEAS Aeronautical Journal, 2019Co-Authors: Mario Natella, Roeland De BreukerAbstract:This paper discusses the effects of the Aerodynamic Model on the design of a composite wing via aeroelastic tailoring. The classic framework for analysis and optimization of composite wings developed at Delft University of Technology adopts panel method Aerodynamics to calculate static and dynamic loads. The current work expands the Aerodynamic Model by including fuselage and horizontal tail. The non-linear trim condition is thus calculated taking into account both moment and force equilibrium. The effect the fuselage and horizontal tail have on the load distribution, and relative position between the Aerodynamic center and the center of gravity translate into different tailored designs for the composite wings. This study provides insights regarding the use of a full-aircraft Aerodynamic Model for aeroelastic tailoring optimization.
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Continuous-time state-space unsteady Aerodynamic Modeling based on boundary element method
Engineering Analysis with Boundary Elements, 2012Co-Authors: Meysam Mohammadi-amin, Behzad Ghadiri, Mostafa Abdalla, Hassan Haddadpour, Roeland De BreukerAbstract:Abstract In this paper a continuous-time state-space Aerodynamic Model is developed based on the boundary element method. Boundary integral equations governing the unsteady potential flow around lifting bodies are presented and modified for thin wing configurations. Next, the BEM discretized problem of unsteady flow around flat wing equivalent to the original geometry is recast into the standard form of a continuous-time state-space Model considering some auxiliary assumptions. The system inputs are time derivative of the instantaneous effective angle of attack and thickness/camber correction terms while the outputs are unsteady Aerodynamic coefficients. To validate the Model, its predictions for Aerodynamic coefficients variations due to the various unsteady motions about different wing geometries are compared to the results of the direct BEM computations and verified numerical and theoretical solutions. This comparison indicates a good agreement. Since the resulting Aerodynamic Model is in the continuous-time domain, it is particularly useful for optimization and nonlinear analysis purposes. Moreover, its state-space representation is the appropriate form for an Aerodynamic Model in design or control applications.
J. A. Mohrfeld-halterman - One of the best experts on this subject based on the ideXlab platform.
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High Fidelity Quasi Steady-State Aerodynamic Model Effects on Race Vehicle Performance Predictions Using Multi-Body Simulation
Vehicle System Dynamics, 2016Co-Authors: J. A. Mohrfeld-halterman, M. UddinAbstract:ABSTRACTWe described in this paper the development of a high fidelity vehicle Aerodynamic Model to fit wind tunnel test data over a wide range of vehicle orientations. We also present a comparison between the effects of this proposed Model and a conventional quasi steady-state Aerodynamic Model on race vehicle simulation results. This is done by implementing both of these Models independently in multi-body quasi steady-state simulations to determine the effects of the high fidelity Aerodynamic Model on race vehicle performance metrics. The quasi steady state vehicle simulation is developed with a multi-body NASCAR Truck vehicle Model, and simulations are conducted for three different types of NASCAR race tracks, a short track, a one and a half mile intermediate track, and a higher speed, two mile intermediate race track. For each track simulation, the effects of the Aerodynamic Model on handling, maximum corner speed, and drive force metrics are analysed. The accuracy of the high-fidelity Model is shown t...
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Quasi steady-state Aerodynamic Model development for race vehicle simulations
Vehicle System Dynamics, 2016Co-Authors: J. A. Mohrfeld-halterman, M. UddinAbstract:Presented in this paper is a procedure to develop a high fidelity quasi steady-state Aerodynamic Model for use in race car vehicle dynamic simulations. Developed to fit quasi steady-state wind tunnel data, the Aerodynamic Model is regressed against three independent variables: front ground clearance, rear ride height, and yaw angle. An initial dual range Model is presented and then further refined to reduce the Model complexity while maintaining a high level of predictive accuracy. The Model complexity reduction decreases the required amount of wind tunnel data thereby reducing wind tunnel testing time and cost. The quasi steady-state Aerodynamic Model for the pitch moment degree of freedom is systematically developed in this paper. This same procedure can be extended to the other five Aerodynamic degrees of freedom to develop a complete six degree of freedom quasi steady-state Aerodynamic Model for any vehicle.
Junseong Lee - One of the best experts on this subject based on the ideXlab platform.
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Aeroelastic analysis of wind turbine blades based on modified strip theory
Journal of Wind Engineering and Industrial Aerodynamics, 2012Co-Authors: Jong-won Lee, Junseong Lee, Jae-hung Han, Hyung-ki ShinAbstract:Abstract This study investigates the performance and aeroelastic characteristics of wind turbine blades based on flexible multibody dynamics, a new Aerodynamic Model, and the fluid–structure interaction approach. A new Aerodynamic Model is proposed based on modified strip theory (MST). MST was established for flapping wing Aerodynamic Models and considers a high relative angle of attack and dynamic stall effects. A simulated wind turbine blade was Modeled using multibody dynamics software (MSC.ADAMS), where the flexible parts can be included by importing a finite element Model built in finite element analysis software (ANSYS). The aeroelastic responses of the blade were obtained by coupling these Aerodynamic and structural Models. The proposed aeroelastic analysis method was validated using the predicted performance of the NREL 5MW Model reported in the literature.
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improved Aerodynamic Model for efficient analysis of flapping wing flight
AIAA Journal, 2011Co-Authors: Dae-kwan Kim, Junseong Lee, Jae-hung HanAbstract:This work was supported by a Korea Research Foundation Grant funded by the Korean Government (MOEHRD) (KRF-2007-313- D00122). The second author would like to thank the Brain Korea 21 Project in 2010. The authors would like to thank James D. DeLaurier of the University of Toronto and M. Okamoto of the Akita National College of Technology for their gracious support for this study. The authors also thank anonymous reviewers and the Editor for their valuable comments and suggestions.
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An aeroelastic analysis of a flexible flapping wing using modified strip theory
Active and Passive Smart Structures and Integrated Systems 2008, 2008Co-Authors: Dae-kwan Kim, Junseong Lee, Jin-young Lee, Jae-hung HanAbstract:The present study proposed a coupling method for the fluid-structural interaction analysis of a flexible flapping wing. An efficient numerical Aerodynamic Model was suggested, which was based on the modified strip theory and further improved to take into account a high relative angle of attack and dynamic stall effects induced by pitching and plunging motions. The Aerodynamic Model was verified with experimental data of rigid wings. A reduced structural Model of a rectangular flapping wing was also established by using flexible multibody dynamics, so as to consider large flapping motions and local elastic deformations. Then, the aeroelastic analysis method was developed by coupling these Aerodynamic and structural modules. To measure the Aerodynamic forces of the rectangular flapping wing, static and dynamic tests were performed in a low speed wind-tunnel for various flapping pitch angles, flapping frequencies and the airspeeds. Finally, the Aerodynamic forces predicted by the aeroelastic analysis method showed good agreement with the experimental data of the rectangular flapping wing.
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Experimental evaluation of a flapping-wing Aerodynamic Model for MAV applications
Active and Passive Smart Structures and Integrated Systems 2008, 2008Co-Authors: Junseong Lee, Dae-kwan Kim, Jin-young Lee, Jae-hung HanAbstract:In the preliminary design phase of the bio-inspired flapping-wing MAV (micro air vehicle), it is necessary to predict the Aerodynamic forces around the flapping-wing under flapping-wing motion at cruising flight. In this study, the efficient quasi-steady flapping-wing Aerodynamic Model for MAV application is explained and it is experimentally verified. The flapping-wing motion is decoupled to the plunging and pitching motion, and the plunging-pitching motion generator with load cell assembly is developed. The compensation of inertial forces from the measured lift and thrust is studied to measure the pure Aerodynamic loads on the flapping-wing. Advanced ratio is introduced to evaluate the unsteadiness of the flow and to make an application range of flapping-wing Aerodynamic Model.
