Aeroelastic stability analysis of hingeless rotor blades in hover using fully intrinsic equations and dynamic wake model

2019 ◽  
Vol 91 (8) ◽  
pp. 1113-1121
Author(s):  
Mohammadreza Amoozgar ◽  
Hossein Shahverdi
Keyword(s):  
Three Dimensional ◽  
Unsteady Aerodynamics ◽  
Rotor Blades ◽  
New Approach ◽  
Content Type ◽  
Aerodynamic Model ◽  
Aeroelastic Analysis ◽  
Beam Equations ◽  
Wake Model ◽  
Composite Blades

PurposeThis paper aims to develop a new approach for aeroelastic analysis of hingeless rotor blades.Design/methodology/approachThe aeroelastic approach developed here is based on the geometrically exact fully intrinsic beam equations and three-dimensional unsteady aerodynamics.FindingsThe developed approach is accurate, fast and very useful in rotorcraft aeroelastic analysis.Originality/valueThis beam formulation has been never combined with three-dimensional aerodynamic model to be used for aeroelastic analysis of blades. In addition, it is possible to handle the composite blades, as well as blades with initial curvatures and twist with this proposed formulation.

scholarly journals Three-Dimensional Aerodynamic Analysis of a Darrieus Wind Turbine Blade Using Computational Fluid Dynamics and Lifting Line Theory

2017 ◽  
Author(s):  
Francesco Balduzzi ◽  
Alessandro Bianchini ◽  
Giovanni Ferrara ◽  
David Marten ◽  
George Pechlivanoglou ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Performance ◽  
Three Dimensional ◽  
Unsteady Aerodynamics ◽  
Cost Effective ◽  
Navier Stokes ◽  
Line Theory ◽  
Wake Model ◽  
Lifting Line

Due to the rapid progress in high-performance computing and the availability of increasingly large computational resources, Navier-Stokes computational fluid dynamics (CFD) now offers a cost-effective, versatile and accurate means to improve the understanding of the unsteady aerodynamics of Darrieus wind turbines and deliver more efficient designs. In particular, the possibility of determining a fully resolved flow field past the blades by means of CFD offers the opportunity to both further understand the physics underlying the turbine fluid dynamics and to use this knowledge to validate lower-order models, which can have a wider diffusion in the wind energy sector, particularly for industrial use, in the light of their lower computational burden. In this context, highly spatially and temporally refined time-dependent three-dimensional Navier-Stokes simulations were carried out using more than 16,000 processor cores per simulation on an IBM BG/Q cluster in order to investigate thoroughly the three-dimensional unsteady aerodynamics of a single blade in Darrieus-like motion. Particular attention was payed to tip losses, dynamic stall, and blade/wake interaction. CFD results are compared with those obtained with an open-source code based on the Lifting Line Free Vortex Wake Model (LLFVW). At present, this approach is the most refined method among the “lower-fidelity” models and, as the wake is explicitly resolved in contrast to BEM-based methods, LLFVW analyses provide three-dimensional flow solutions. Extended comparisons between the two approaches are presented and a critical analysis is carried out to identify the benefits and drawbacks of the two approaches.

scholarly journals Three-Dimensional Aerodynamic Analysis of a Darrieus Wind Turbine Blade Using Computational Fluid Dynamics and Lifting Line Theory

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Francesco Balduzzi ◽  
David Marten ◽  
Alessandro Bianchini ◽  
Jernej Drofelnik ◽  
Lorenzo Ferrari ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Performance ◽  
Three Dimensional ◽  
Unsteady Aerodynamics ◽  
Cost Effective ◽  
Navier Stokes ◽  
Line Theory ◽  
Wake Model ◽  
Lifting Line

Due to the rapid progress in high-performance computing and the availability of increasingly large computational resources, Navier–Stokes (NS) computational fluid dynamics (CFD) now offers a cost-effective, versatile, and accurate means to improve the understanding of the unsteady aerodynamics of Darrieus wind turbines and deliver more efficient designs. In particular, the possibility of determining a fully resolved flow field past the blades by means of CFD offers the opportunity to both further understand the physics underlying the turbine fluid dynamics and to use this knowledge to validate lower-order models, which can have a wider diffusion in the wind energy sector, particularly for industrial use, in the light of their lower computational burden. In this context, highly spatially and temporally refined time-dependent three-dimensional (3D) NS simulations were carried out using more than 16,000 processor cores per simulation on an IBM BG/Q cluster in order to investigate thoroughly the 3D unsteady aerodynamics of a single blade in Darrieus-like motion. Particular attention was paid to tip losses, dynamic stall, and blade/wake interaction. CFD results are compared with those obtained with an open-source code based on the lifting line free vortex wake model (LLFVW). At present, this approach is the most refined method among the “lower-fidelity” models, and as the wake is explicitly resolved in contrast to blade element momentum (BEM)-based methods, LLFVW analyses provide 3D flow solutions. Extended comparisons between the two approaches are presented and a critical analysis is carried out to identify the benefits and drawbacks of the two approaches.

Generic Modeling and Parametric Study of Flapping Wing Micro-Air-Vehicle

2012 ◽  
Vol 225 ◽  
pp. 18-25 ◽  
Author(s):  
Harijono Djojodihardjo ◽  
Alif Syamim Syazwan Ramli ◽  
Surjatin Wiriadidjaja
Keyword(s):  
Parametric Study ◽  
Three Dimensional ◽  
Unsteady Aerodynamics ◽  
Flapping Wing ◽  
Phase Lag ◽  
Aerodynamic Model ◽  
Strip Theory ◽  
Thrust Characteristics ◽  
Generic Modeling ◽  
Wing Geometry

The present work is focused on the unsteady aerodynamics of bio-inspired flapping wing to produce lift and thrust for hovering and forward flight. A generic approach is followed to understand and mimic the mechanism and kinematics of ornithopter by considering the motion of a three-dimensional rigid thin wing in flapping and pitching motion, using strip theory and two-dimensional unsteady aerodynamics for idealized wing in pitching and flapping oscillations with phase lag. Parametric study is carried out to obtain the lift, drag, and thrust characteristics within a cycle for assessing the plausibility of the aerodynamic model, and for the synthesis of a Flapping Wing MAV model with simplified mechanism. Other important parameters such as flapping frequency and wing geometry are considered. Results are assessed in comparison with the existing theoretical results.

scholarly journals Further Development of the Kinematic and Aerodynamic Modeling and Analysis of Flapping Wing Ornithopter from Basic Principles

2014 ◽  
Vol 629 ◽  
pp. 9-17
Author(s):  
Harijono Djojodihardjo ◽  
Muhammad Anas Abd Bari ◽  
Azmin Shakrine Mohd Rafie ◽  
Surjatin Wiriadidjaja
Keyword(s):  
Three Dimensional ◽  
Unsteady Aerodynamics ◽  
Flapping Wing ◽  
Phase Lag ◽  
Basic Principles ◽  
Modeling And Analysis ◽  
Aerodynamic Modeling ◽  
Aerodynamic Model ◽  
Strip Theory ◽  
Further Development

<p>The basis of this work was to understand the generation of lift and thrust of a flapping bi-wing ornithopter, which is influenced by its geometrical, dynamic, kinematic and aerodynamic features by following a generic approach in order to identify and mimic the mechanisms. As further development of earlier work, three-dimensional rigid thin wing is considered in flapping and pitching motion using strip theory and two-dimensional unsteady aerodynamics for idealized wing in pitching and flapping oscillations with phase lag. Later, parametric study is carried out to attain a complete cycle’s lift and thrust physical characteristics for evaluating the plausibility of the aerodynamic model and for the synthesis of an ornithopter model with simplified mechanism. Further investigation is conducted to identify individual contribution of generic motion towards the flight forces. Results are assessed in comparison with existing theoretical and experimental results as appropriate.</p>

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.

Effect of Three-Dimensional Aerodynamics and Dynamic Stall on Lead–Lag Damping of an Isolated Rotor

2021 ◽  
Vol 66 (1) ◽  
pp. 1-13
Author(s):  
Vellingiri Ramanujam R ◽  
Ranjith Mohan
Keyword(s):  
Radial Flow ◽  
Three Dimensional ◽  
Dynamic Stall ◽  
Forward Flight ◽  
Dimensional Effects ◽  
Flow Coupling ◽  
Aerodynamic Model ◽  
Wake Model ◽  
Torsionally Stiff ◽  
Edge Separation

This paper investigates three-dimensional aerodynamic effects due to radial flow on lead–lag damping of a rotor in forward flight conditions. Three-dimensional effects in this study are restricted to yawed flow aerodynamics and radial flow coupling between blade segments. These effects are included in the ONERA dynamic stall model, and lead–lag damping for an isolated torsionally stiff rotor is calculated for different forward flight conditions. This augmented aerodynamic model with three-dimensional effects and Peters–He dynamic wake model improves the correlation of lead–lag damping with experimental data at high advance ratios. The effect of modeling static lift characteristics on damping correlation is also presented. Finally, a modification to the trailing edge separation point–based static lift model for improved yawed flow modeling amenable to aeromechanical stability analysis is proposed.

scholarly journals Three-Dimensional CST Parameterization Method Applied in Aircraft Aeroelastic Analysis

2017 ◽  
Vol 2017 ◽  
pp. 1-15
Author(s):  
Hua Su ◽  
Chunlin Gong ◽  
Liangxian Gu
Keyword(s):  
Structural Model ◽  
Three Dimensional ◽  
Automatic Process ◽  
Shape Transformation ◽  
Design And Optimization ◽  
Aerodynamic Model ◽  
Conceptual Design Phase ◽  
Design Variables ◽  
Aeroelastic Analysis ◽  
Aeroelastic Model

Class/shape transformation (CST) method has advantages of adjustable design variables and powerful parametric geometric shape design ability and has been widely used in aerodynamic design and optimization processes. Three-dimensional CST is an extension for complex aircraft and can generate diverse three-dimensional aircraft and the corresponding mesh automatically and quickly. This paper proposes a parametric structural modeling method based on gridding feature extraction from the aerodynamic mesh generated by the three-dimensional CST method. This novel method can create parametric structural model for fuselage and wing and keep the coordination between the aerodynamic mesh and the structural mesh. Based on the generated aerodynamic model and structural model, an automatic process for aeroelastic modeling and solving is presented with the panel method for aerodynamic solver and NASTRAN for structural solver. A reusable launch vehicle (RLV) is used to illustrate the process for aeroelastic modeling and solving. The result shows that this method can generate aeroelastic model for diverse complex three-dimensional aircraft automatically and reduce the difficulty of aeroelastic analysis dramatically. It provides an effective approach to make use of the aeroelastic analysis at the conceptual design phase for modern aircraft.

Investigation on spatial distribution and evolution features of the running-in attractor based on a new approach

2018 ◽  
Vol 70 (9) ◽  
pp. 1636-1641
Author(s):  
Cong Ding ◽  
Hua Zhu ◽  
Guodong Sun ◽  
Chun Ling Wei ◽  
Yu Jiang
Keyword(s):  
Spatial Distribution ◽  
Friction Coefficient ◽  
Design Methodology ◽  
Three Dimensional ◽  
New Approach ◽  
Dynamic Behaviors ◽  
Content Type ◽  
Evolution Rule ◽  
Uniform State ◽  
Variation Tendency

Purpose The purpose of this work is to comprehensively reveal the spatial distribution and evolution features of a running-in attractor. Design/methodology/approach The friction coefficient signals extracted from wear experiments are reconstructed. A projected matrix is obtained based on the reconstructed matrix. Then the approach of three-dimensional (3D) histogram of phase points is proposed, which is used to intuitively characterize the complex properties of the running-in attractor. Findings The space occupied by the running-in attractor gradually contracts, then stabilizes and finally expands; the maximum of phase points number in a certain bin initially decreases, then keeps stable and finally increases rapidly; yet the percentage of bins number storing phase points shows an inverse variation tendency. Consequently, 3D histogram evolves from a nonuniform state to a uniform state then returns back to the nonuniform state, which indicates the evolution rule of “formation, stabilization and disappearance” of the running-in attractor. Originality/value Characterization on the features of the running-in attractor can provide valuable information about friction systems and their dynamic behaviors.

Continued Validation of the AeroDyn Subroutines Using NREL Unsteady Aerodynamics Experiment Data

2003 ◽  
Author(s):  
David J. Laino ◽  
A. Craig Hansen
Keyword(s):  
Time Lag ◽  
Unsteady Aerodynamics ◽  
Rotor Blades ◽  
Dynamic Stall ◽  
Experiment Data ◽  
3 Dimensional ◽  
Pitch Change ◽  
Yaw Rate ◽  
Wind Turbine Aerodynamics ◽  
Wake Model

Full-scale wind tunnel tests of the NREL Unsteady Aerodynamics Experiment (UAE) Phase VI permitted unprecedented control and measurement of inflow to the UAE rotor. This in turn has allowed in-depth validation of the AeroDyn wind turbine aerodynamics software. This validation began with comparison of simple cases (i.e., fixed yaw, fixed pitch, no teeter), with results presented last year [2]. Among the findings of that study was the significant increase in section lift along the rotor blades due to the 3–dimensional flow over the UAE rotor. This delayed stall was not adequately accounted for in the AeroDyn model. This continued validation effort looks into delayed stall and the static and dynamic behavior of the Generalized Dynamic Wake (GDW) model in AeroDyn. Validation is accomplished through comparison of UAE data and simulation results for the following cases: • Uniform inflow (upwind, zero yaw error), • Step pitch changes on an operating rotor, • A teetering rotor at various yaw angles, and • Downwind rotor released into flee yaw from various initial yaw error positions. Results presented allow us to draw several conclusions. The Du and Selig delayed stall correction adequately models the increase in CL, but the suggested decrease in CD of that model does not agree with observations in the data. The time lag coefficient in the GDW model agrees well with observations in the rapid pitch change UAE data. The phase of teeter response for the GDW model agrees better with data than for the equilibrium wake model. Dynamic stall provides significant additional damping to the teeter motion. The choice of wake model also greatly affects the yaw rate in the yaw release simulations.

New semi three-dimensional approach for simulation of Lamb wave clamp-on ultrasonic gas flowmeter

Sensor Review ◽  
2020 ◽  
Vol 40 (4) ◽  
pp. 465-476
Author(s):  
Seyed Foad Mousavi ◽  
Seyed Hassan Hashemabadi ◽  
Jalil Jamali
Keyword(s):  
Lamb Wave ◽  
Gas Flow ◽  
Computing Time ◽  
Three Dimensional ◽  
Dimensional Approach ◽  
Three Dimensional Model ◽  
Contact Mode ◽  
New Approach ◽  
Content Type ◽  
2D Simulation

Purpose The purpose of this study is to numerically simulate the Lamb wave propagation through a clamp-on ultrasonic gas flowmeter (UGF) in contact mode, using a new semi three-dimensional approach. Moreover, experimental and analytical modeling results for transit time difference method have been used to confirm the simulation results at different gas flow velocities from 0.3 to 2.4 m/s. Design/methodology/approach The new semi three-dimensional approach involves the simulation of the flow field of the gas in a three-dimensional model and subsequently the simulation of wave generation, propagation and reception in a two-dimensional (2D) model. Moreover, the analytical model assumes that the wave transitions occur in a 2D mode. Findings The new approach is a semi three-dimensional approach used in this work, has better accuracy than a complete 2D simulation while maintaining the computing time and costs approximately constant. It is faster and less expensive than a complete 3D simulation and more accurate than a complete 2D simulation. It was concluded that the new approach could be extended to simulate all types of ultrasonic gas and non-gas flowmeters, even under harsh conditions. Originality/value In this work, a new approach for the numerical simulation of all types of ultrasonic flowmeters is introduced. It was used for simulation of a Lamb wave ultrasonic flow meter in contact mode.

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