Multiobjective Design Study of a Flapping Wing Power Generator

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Eriko Shimizu ◽  
Koji Isogai ◽  
Shigeru Obayashi
Keyword(s):  
Data Mining ◽  
Flapping Wing ◽  
Phase Delay ◽  
Dynamic Stall ◽  
Design Parameters ◽  
Objective Functions ◽  
Design Study ◽  
Power Generator ◽  
Trade Off ◽  
Reduced Frequency

In conventional windmills, the high tip speed creates aerodynamic noise, and when they are used at very low Reynolds numbers, their performance deteriorates due to laminar separation. These are important issues in modern windmills. Present study deals with a new windmill concept, the “flapping wing power generator,” which would solve such problems. The concept is to extract energy via the flutter phenomena and the concept has been developed by some researchers. In 2003, Isogai et al. 2003, “Design Study of Elastically Supported Flapping Wing Power Generator,” International Forum on Aeroelasticity and Structural Dynamics, Amsterdam) proposed a new system. The system utilizes dynamic stall vortices efficiently and generates high power. The dynamic stall vortex is something that should be avoided in conventional windmills. They optimized the system to maximize the efficiency and obtained the set of design parameters, which achieved best efficiency. The system works at low frequencies and it enables high efficiency. To realize the system, it is necessary to consider the power and the efficiency. Thus, the present study optimized the system to maximize both the power and the efficiency. To obtain nondominated solutions, which are widely distributed in the design space, adaptive neighboring search, which is one of evolutionary algorithms, has been extended to handle multiple objectives and was used in the present study. Self-organizing map was used for the data mining. The trade-off between the power and the efficiency has been visualized. The trade-off curve was shaped by the constraints on the reduced frequency and the phase delay angle, which were imposed so that the dynamic stall phenomenon gives favorable effects on the power generation. The heaving amplitude was a parameter correlated to the objective functions. The reduced frequency and the phase delay angle change to control the heaving amplitude. Consequently, when the power is emphasized, the system undergoes a large heaving motion with a low frequency. On the other hand, when the efficiency is emphasized, the system undergoes a small heaving motion with a high frequency. Multiobjective optimization and data mining revealed the trade-off of the objective functions and the parameters correlated to the objective functions. The power obtained was comparable to that of present windmills at low tip-speed ratio region.

scholarly journals Performance Enhancement of the Micromixer by the Multiobjective Genetic Algorithm and Surrogate Model Based on a Navier–Stokes Analysis Using Trade-Off Objective Functions

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Shakhawat Hossain ◽  
Farzana Islam ◽  
Nass Toufik Tayeb ◽  
Muhammad Aslam ◽  
Jin-Hyuk Kim
Keyword(s):  
Genetic Algorithm ◽  
Surrogate Model ◽  
Performance Enhancement ◽  
Channel Width ◽  
Navier Stokes ◽  
Design Parameters ◽  
Design Domain ◽  
Objective Functions ◽  
Trade Off ◽  
Multiobjective Genetic Algorithm

Optimal structure of the micromixer with a two-layer serpentine crossing device was accomplished by a multiobjective genetic algorithm and surrogate modeling based on a Navier–Stokes analysis using the trade-off objective functions behavior. The optimization analysis was conducted with three design parameters, i.e., channel width to the pitch span ( w / P ) ratio, major channel width to the pitch span (H/P) ratio, and channel depth to the pitch span (d/P) ratio. Two objective functions (i.e., mixing index and pressure drop) with trade-off characteristics have been used to solve the multiobjective optimization problem. The design domain was predetermined by a parametric investigation; afterward, the Latin hypercube sampling method was employed to select the appropriate design points surrounded by the design domain. The numerical data of the thirty-two design points were used to create the surrogate model; among the different surrogate models, in this study, the Kriging metamodel has been used. The concave pareto-optimal curve signifies the trade-off characteristics linking the objective functions.

Dynamic Stall Simulation of Flow Over NACA0012 Airfoil at 1 Million Reynolds Number

2015 ◽  
Author(s):  
Venkata Ravishankar Kasibhotla ◽  
Danesh Tafti
Keyword(s):  
Reynolds Number ◽  
Flow Field ◽  
Lift Coefficient ◽  
Three Dimensional ◽  
Dynamic Stall ◽  
Sharp Drop ◽  
Airfoil Surface ◽  
Naca0012 Airfoil ◽  
Reduced Frequency ◽  
Edge Vortex

The paper is concerned with the prediction and analysis of dynamic stall of flow past a pitching NACA0012 airfoil at 1 million Reynolds number based on the chord length of the airfoil and at reduced frequency of 0.25 in a three dimensional flow field. The turbulence in the flow field is resolved using large eddy simulations with the dynamic Smagorinsky model at the sub grid scale. The development of dynamic stall vortex, shedding and reattachment as predicted by the present study are discussed in detail. This study has shown that the downstroke phase of the pitching motion is strongly three dimensional and is highly complex, whereas the flow is practically two dimensional during the upstroke. The lift coefficient agrees well with the measurements during the upstroke. However, there are differences during the downstroke. The computed lift coefficient undergoes a sharp drop during the start of the downstroke as the convected leading edge vortex moves away from the airfoil surface. This is followed by a recovery of the lift coefficient with the formation of a secondary trailing edge vortex. While these dynamics are clearly reflected in the predicted lift coefficient, the experimental evolution of lift during the downstroke maintains a fairly smooth and monotonic decrease in the lift coefficient with no lift recovery. The simulations also show that the reattachment process of the stalled airfoil is completed before the start of the upstroke in the subsequent cycle due to the high reduced frequency of the pitching cycle.

Trade-Off Analysis for the Design of a High Performance Hydrostatic Actuation System

2000 ◽  
Author(s):  
S. R. Habibi
Keyword(s):  
Mathematical Modeling ◽  
Quadratic Programming ◽  
High Performance ◽  
Design Parameters ◽  
Mathematical Functions ◽  
Trade Off ◽  
Actuation System ◽  
Trade Offs ◽  
Expected Performance ◽  
Dominant Design

Abstract This paper considers the design of a high performance hydrostatic actuation system referred to as the ElectroHydraulic Actuator (EHA). The expected performance of EHA and its dominant design parameters are identified by using mathematical modeling. The design parameters are classified into Direct and Indirect categories based on the measure of their accessibility to the designer. The Direct parameters are directly quantifiable and, can be linked to the performance of EHA through a set of mathematical functions. A prototype of EHA has been produced and described. The mathematical functions linking performance to design parameters are used to investigate design trade-offs. Design improvements to the prototype are suggested by using constrained quadratic programming.

Flight Characteristics of Flapping Wing Miniature Air Vehicles With “Figure-8” Spherical Motion

2009 ◽  
Author(s):  
Mohamed B. Trabia ◽  
Woosoon Yim ◽  
Zohaib Rehmat ◽  
Jesse Roll
Keyword(s):  
Mathematical Model ◽  
Wind Tunnel ◽  
Experimental Testing ◽  
Flapping Wing ◽  
Dynamic Stall ◽  
Wind Tunnel Testing ◽  
Servo Motor ◽  
Aerodynamic Forces ◽  
Flapping Motion ◽  
Spherical Motion

Hummingbirds and some insects exhibit “Figure-8” flapping motion that allows them to go through a variety of maneuvers including hovering. Understanding the flight characteristics of Figure-8 flapping motion can potentially yield the foundation of flapping wing UAVs that can experience similar maneuverability. In this paper, a mathematical model of the dynamic and aerodynamic forces associated with Figure-8 motion generated by a spherical four bar mechanism is developed. For validation, a FWMAV prototype with the wing attached to a coupler point and driven by a DC servo motor is created for experimental testing. Wind tunnel testing is conducted to determine the coefficients of flight and the effects of dynamic stall. The wing is driven at speeds up to 12.25 Hz with results compared to that of the model. The results indicate good correlation between mathematical model and experimental prototype.

Optimal design of a parallel robotic gripper using enhanced multi-objective ant lion optimizer with a sensitivity analysis approach

2020 ◽  
Vol 40 (5) ◽  
pp. 703-721
Author(s):  
Golak Bihari Mahanta ◽  
Deepak BBVL ◽  
Bibhuti B. Biswal ◽  
Amruta Rout
Keyword(s):  
Sensitivity Analysis ◽  
Distribution Function ◽  
Design Parameters ◽  
Objective Functions ◽  
Content Type ◽  
Multi Objective ◽  
The Past ◽  
Design Variables ◽  
Pick And Place ◽  
Ant Lion

Purpose From the past few decades, parallel grippers are used successfully in the automation industries for performing various pick and place jobs due to their simple design, reliable nature and its economic feasibility. So, the purpose of this paperis to design a suitable gripper with appropriate design parameters for better performance in the robotic production systems. Design/methodology/approach In this paper, an enhanced multi-objective ant lion algorithm is introduced to find the optimal geometric and design variables of a parallel gripper. The considered robotic gripper systems are evaluated by considering three objective functions while satisfying eight constraint equations. The beta distribution function is introduced for generating the initial random number at the initialization phase of the proposed algorithm as a replacement of uniform distribution function. A local search algorithm, namely, achievement scalarizing function with multi-criteria decision-making technique and beta distribution are used to enhance the existing optimizer to evaluate the optimal gripper design problem. In this study, the newly proposed enhanced optimizer to obtain the optimum design condition of the design variables is called enhanced multi-objective ant lion optimizer. Findings This study aims to obtain optimal design parameters of the parallel gripper with the help of the developed algorithms. The acquired results are investigated with the past research paper conducted in that field for comparison. It is observed that the suggested method to get the best gripper arrangement and variables of the parallel gripper mechanism outperform its counterparts. The effects of the design variables are needed to be studied for a better design approach concerning the objective functions, which is achieved by sensitivity analysis. Practical implications The developed gripper is feasible to use in the assembly operation, as well as in other pick and place operations in different industries. Originality/value In this study, the problem to find the optimum design parameter (i.e. geometric parameters such as length of the link and parallel gripper joint angles) is addressed as a multi-objective optimization. The obtained results from the execution of the algorithm are evaluated using the performance indicator algorithm and a sensitivity analysis is introduced to validate the effects of the design variables. The obtained optimal parameters are used to develop a gripper prototype, which will be used for the assembly process.

Experimental Study on a Cascade Flapping Wing Hydroelectric Power Generator

2011 ◽  
Author(s):  
Hisanori Abiru ◽  
Akira Yoshitake
Keyword(s):  
Power Generation ◽  
Electric Motor ◽  
Flapping Wing ◽  
Hydroelectric Power ◽  
Power Generator ◽  
Flow Energy ◽  
Wing Model ◽  
Leaf Springs ◽  
Hydroelastic Response ◽  
Elastically Supported

In this paper, a hydroelectric power generator that can extract the water flow energy from the hydroelastic response of an elastically supported rectangular wing is experimentally investigated. An electric motor is used to excite pitching oscillations of the wing. The wing and the electric motor are supported by leaf springs that are designed to function both as a linear guide for the sway oscillations and as elastic elements. The wing mass in the sway direction necessary to achieve a hydroelastic response is obtained by utilizing a mechanical snubber mechanism. The load to generate electricity is provided equivalently by magnetic dampers. In a previous paper, the power generation rate and the efficiency of a single-wing model were examined through experiments, and the feasibility of a flapping wing hydroelectric power generator was verified. In this paper, the influence of neighboring wings is examined by using two experimental apparatuses with the intention of achieving a practical cascade-wing generator. Tests showed that a cascade moving in-phase with neighboring wings with smaller gaps between the wings has a higher rate of electric power generation.

Architecture Optmization of a 3-DOF Parallel Mechanism

1998 ◽  
Author(s):  
J. A. Carretero ◽  
R. P. Podhorodeski ◽  
M. Nahon
Keyword(s):  
Parallel Mechanism ◽  
Architectural Design ◽  
Degrees Of Freedom ◽  
Jacobian Matrix ◽  
Design Parameters ◽  
Objective Functions ◽  
Constraint Equations ◽  
Three Degree Of Freedom ◽  
Architecture Optimization ◽  
Three Degrees Of Freedom

Abstract This paper presents a study of the architecture optimization of a three-degree-of-freedom parallel mechanism intended for use as a telescope mirror focussing device. The construction of the mechanism is first described. Since the mechanism has only three degrees of freedom, constraint equations describing the inter-relationship between the six Cartesian coordinates are given. These constraints allow us to define the parasitic motions and, if incorporated into the kinematics model, a constrained Jacobian matrix can be obtained. This Jacobian matrix is then used to define a dexterity measure. The parasitic motions and dexterity are then used as objective functions for the optimizations routines and from which the optimal architectural design parameters are obtained.

Nanosecond dielectric barrier discharge–based dynamic stall control on an SC-1095 airfoil

2020 ◽  
pp. 095965182094582
Author(s):  
He-sen Yang ◽  
Hua Liang ◽  
Guang-yin Zhao
Keyword(s):  
Dielectric Barrier Discharge ◽  
Barrier Discharge ◽  
Actuation Voltage ◽  
Dynamic Stall ◽  
Effective Control ◽  
Control Effect ◽  
Actuation Frequency ◽  
Dielectric Barrier ◽  
Reduced Frequency ◽  
Dependent Flow

Dynamic stall is a time-dependent flow separation and stall phenomenon that is present in many applications, including violently maneuvering aircraft, surging compressor, wind turbine, and, most observably, rotorcraft. Nanosecond dielectric barrier discharge plasma actuator has previously demonstrated the control ability in static stall conditions and shows promise to address dynamic stall. The present work explores the ability of nanosecond dielectric barrier discharge to control dynamic stall over an SC-1095 airfoil and summarizes the control law of actuation parameters. The actuation voltage, actuation frequency, and reduced frequencies were varied over large ranges: Vp–p = 7–13 kV, F+ = 0.5–10, and k = 0.05–0.15. Direct aerodynamic measurements were taken for each combination of actuation voltages and actuation frequencies, and fixed combination at different experimental reduced frequencies. It was observed that nanosecond dielectric barrier discharge could effectively improve the dynamic stall characteristics, and three major conclusions were drawn. First, there is a threshold for actuation voltage. Only when the actuation voltage is greater than or equal to the threshold voltage can the separation be effectively suppressed and the steep stall can be alleviated. Second, High F+ has better control performance of maintaining peak lift in the stall regime and achieves better effects in moment control and drag reduction while lift reattachment is better with low F+ on downstroke. Last, with the increase of reduced frequency, the control effect of nanosecond dielectric barrier discharge with settled actuation parameter combination becomes worse, so greater cost needs to be paid for effective control at a larger reduced frequency.

The Effect of Elevated Guideway Construction Tolerances on Vehicle Ride Quality

1975 ◽  
Vol 97 (4) ◽  
pp. 408-416 ◽  
Author(s):  
J. K. Hedrick ◽  
R. J. Ravera ◽  
J. R. Anderes
Keyword(s):  
Cross Section ◽  
Quality Criteria ◽  
Design Parameters ◽  
Ride Quality ◽  
Live Load ◽  
General Technique ◽  
Trade Off ◽  
Frequency Decomposition ◽  
Space Boundary

In this paper the ride quality of a vehicle traversing an elevated guideway is related directly to guideway construction tolerances and design parameters. Moreover, the construction tolerances are modeled in terms familiar to a guideway contractor. The tolerances modeled for an elevated, two-span semicontinuous, concrete guideway are: surface finish, camber deviations, pier survey errors, and pier settlement. The major design parameters relating to live-load deflection, stiffness (material and cross-section), and pier spacing are included. A general technique is presented for relating these tolerances to vehicle ride quality by means of a digital computer simulation. Various ride quality criteria are considered, including rms acceleration, acceleration spectral density, acceleration frequency decomposition, and a deterministic state space boundary. Numerical results are presented for a particular vehicle-guideway configuration and as such are valid only for the system considered. It is shown that for this system, equivalent ride quality can be maintained while adjusting the various construction tolerances. This trade-off capability allows the contractor to choose the least costly combination of tolerance parameters.

Flutter of Mistuned Turbomachinery Rotors

1984 ◽  
Vol 106 (1) ◽  
pp. 25-33 ◽  
Author(s):  
O. O. Bendiksen
Keyword(s):  
Perturbation Methods ◽  
Arbitrary Order ◽  
Design Parameters ◽  
Complex Conjugate ◽  
Form Complex ◽  
Stable Mode ◽  
Single Degree Of Freedom ◽  
Reduced Frequency ◽  
Left And Right ◽  
The Stability

An investigation of the fundamental aspects of flutter in mistuned turbomachinery rotors is presented. Perturbation methods are used to obtain asymptotic solutions to arbitrary order in the mistuning parameter. These solutions require only the knowledge of the eigensolution of the tuned system, and thus provide efficient formulas for calculating the effect of mistuning without solving a new eigenvalue problem. Numerical results presented for design parameters representative of fan rotors indicate that a critical reduced frequency exists, below which mistuning alone cannot stabilize the rotor. The sensitivity of the stability boundaries to mistuning was found to depend fundamentally on relations between the left and right eigenvectors. For systems where the left and right eigenvectors form complex conjugate pairs, mistuning cannot destabilize the system unless the reduced frequency of the least stable mode is decreased by the perturbation. In general, only cascades and rotors with a single degree-of-freedom per blade belong to this class.

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