The Experts below are selected from a list of 5766 Experts worldwide ranked by ideXlab platform
Murat Özen - One of the best experts on this subject based on the ideXlab platform.
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Structural-Response Analysis, Fatigue-Life Prediction, and Material Selection for 1 MW Horizontal-Axis Wind-Turbine Blades
Journal of Materials Engineering and Performance, 2010Co-Authors: Mica Grujicic, Antonio Vallejo, E. Subramanian, Velmurugan Sellappan, Guruprasad Arakere, Murat ÖzenAbstract:The problem of mechanical design, performance prediction (e.g., flap-wise / edge-wise bending stiffness, fatigue-controlled life, the extent of bending-to-torsion coupling), and material selection for a prototypical 1 MW horizontal-axis wind turbine (HAWT) blade is investigated using various computer-aided engineering tools. For example, a computer program was developed which can automatically generate both a geometrical model and a full finite-element input deck for a given single HAWT-blade with a given Airfoil Shape, size, and the type and position of the interior load-bearing longitudinal beam/shear-webs. In addition, composite-material laminate lay-up can be specified and varied in order to obtain a best combination of the blade aerodynamic efficiency and longevity. A simple procedure for HAWT-blade material selection is also developed which attempts to identify the optimal material candidates for a given set of functional requirements, longevity and low weight.
U Selvakumar - One of the best experts on this subject based on the ideXlab platform.
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Application of non- traditional optimization techniques for Airfoil Shape optimization”, Modeling and Simulation
2020Co-Authors: R Mukesh, K Lingadurai, U SelvakumarAbstract:The method of optimization algorithms is one of the most important parameters which will strongly influence the fidelity of the solution during an aerodynamic Shape optimization problem. Nowadays, various optimization methods, such as genetic algorithm (GA), simulated annealing (SA), and particle swarm optimization (PSO), are more widely employed to solve the aerodynamic Shape optimization problems. In addition to the optimization method, the geometry parameterization becomes an important factor to be considered during the aerodynamic Shape optimization process. The objective of this work is to introduce the knowledge of describing general Airfoil geometry using twelve parameters by representing its Shape as a polynomial function and coupling this approach with flow solution and optimization algorithms. An aerodynamic Shape optimization problem is formulated for NACA 0012 Airfoil and solved using the methods of simulated annealing and genetic algorithm for 5.0 deg angle of attack. The results show that the simulated annealing optimization scheme is more effective in finding the optimum solution among the various possible solutions. It is also found that the SA shows more exploitation characteristics as compared to the GA which is considered to be more effective explorer
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Airfoil Shape optimization using non traditional optimization technique and its validation
Journal of King Saud University: Engineering Sciences, 2014Co-Authors: R Mukesh, K Lingadurai, U SelvakumarAbstract:Abstract Computational fluid dynamics (CFD) is one of the computer-based solution methods which is more widely employed in aerospace engineering. The computational power and time required to carry out the analysis increase as the fidelity of the analysis increases. Aerodynamic Shape optimization has become a vital part of aircraft design in the recent years. Generally if we want to optimize an Airfoil we have to describe the Airfoil and for that, we need to have at least hundred points of x and y co-ordinates. It is really difficult to optimize Airfoils with this large number of co-ordinates. Nowadays many different schemes of parameter sets are used to describe general Airfoil such as B-spline, and PARSEC. The main goal of these parameterization schemes is to reduce the number of needed parameters as few as possible while controlling the important aerodynamic features effectively. Here the work has been done on the PARSEC geometry representation method. The objective of this work is to introduce the knowledge of describing general Airfoil using twelve parameters by representing its Shape as a polynomial function. And also we have introduced the concept of Genetic Algorithm to optimize the aerodynamic characteristics of a general Airfoil for specific conditions. A MATLAB program has been developed to implement PARSEC, Panel Technique, and Genetic Algorithm. This program has been tested for a standard NACA 2411 Airfoil and optimized to improve its coefficient of lift. Pressure distribution and co-efficient of lift for Airfoil geometries have been calculated using the Panel method. The optimized Airfoil has improved co-efficient of lift compared to the original one. The optimized Airfoil is validated using wind tunnel data.
Leifur Leifsson - One of the best experts on this subject based on the ideXlab platform.
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supersonic Airfoil Shape optimization by variable fidelity models and manifold mapping
International Conference on Computational Science, 2016Co-Authors: Jacob Siegler, Jie Ren, Leifur Leifsson, Slawomir Koziel, Adrian BekasiewiczAbstract:Supersonic vehicles are an important type of potential transports. Analysis of these vehicles requires the use of accurate models, which are also computationally expensive, to capture the highly nonlinear physics. This paper presents results of numerical investigations of using physics-based surrogate models to design supersonic Airfoil Shapes. Variable-fidelity models are generated using inviscid computational fluid dynamics simulations and analytical models. By using response correction techniques, in particular, the manifold mapping technique, fast surrogate models are constructed. The effectiveness of the approach is investigated using lift-constrained drag minimization problems of supersonic Airfoil Shapes. Compared with direct optimization, the results show that an order of magnitude speed up can be obtained. Furthermore, we investigate the effectiveness of the variable-fidelity technique in terms of speed and design quality using several combinations of medium-fidelity and low-fidelity models.
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multi level cfd based Airfoil Shape optimization with automated low fidelity model selection
International Conference on Conceptual Structures, 2013Co-Authors: Slawomir Koziel, Leifur LeifssonAbstract:Abstract Computational fluid dynamic (CFD) models are ubiquitous in aerodynamic design. Variable-fidelity optimization algorithms have proven to be computationally efficient and therefore suitable to reduce high CPU-cost related to the design process solely based on accurate CFD models. A convenient way of constructing the variable-fidelity models is by using the high-fidelity solver, but with a varying degree of discretization and reduced number of flow solver iterations. So far, selection of the appropriate parameters has only been guided by the designer experience. In this paper, an automated low- fidelity model selection technique is presented. By defining the problem as a constrained nonlinear optimization problem, suitable grid and flow solver parameters are obtained. Our approach is compared to conventional methods of generating a family of variable-fidelity models. Comparison of the standard and the proposed approaches in the context of aerodynamic design of a transonic Airfoil indicates that the automated model generation can yield significant computational savings.
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knowledge based Airfoil Shape optimization using space mapping
30th AIAA Applied Aerodynamics Conference, 2012Co-Authors: Slawomir Koziel, Leifur LeifssonAbstract:A computationally efficient optimization methodology for transonic Airfoil design is presented. A direct optimization of the expensive high-fidelity computational fluid dynamics (CFD) Airfoil model is replaced by an iterative updating and re-optimization of a cheap surrogate model. The surrogate is constructed using the low-fidelity model which is based on the same governing fluid flow equations as the high-fidelity model, but uses coarser mesh resolution and relaxed convergence criteria. The low-fidelity model undergoes suitable corrections to become a reliable representation of the high-fidelity one so that it can be subsequently used to find an approximate optimum design of the latter. The corrections are implemented using space mapping. To our knowledge, it is one of the first applications of space mapping to aerodynamic Shape optimization. Our method is applied to constrained Airfoil lift maximization and drag minimization in two-dimensional inviscid transonic flow. The optimized designs are obtained at substantially lower computational cost when compared to the direct high-fidelity model optimization.
Sandra Velardesuarez - One of the best experts on this subject based on the ideXlab platform.
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an optimized Airfoil geometry for vertical axis wind turbine applications
International Journal of Green Energy, 2020Co-Authors: Andres Meanafernandez, Lorena Diazartos, J Fernandez M Oro, Sandra VelardesuarezAbstract:ABSTRACTIn this work, a new Airfoil Shape optimized for vertical-axis wind turbine applications is proposed. Different Airfoil Shapes have been analyzed with JavaFoil, a panel method software. Then...
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proposal of an optimized Airfoil geometry for vertical axis wind turbine applications
2018Co-Authors: Andres Meanafernandez, Lorena Diazartos, Jesus Manuel Fernandez Oro, Sandra VelardesuarezAbstract:In this work, an Airfoil geometry optimized for vertical-axis wind turbine applications is presented. Different Airfoil Shapes have been analyzed with JavaFoil, a panel method software. Then, the results from the analysis have been used to optimize the performance of the proposed Airfoil Shape (UO-17-LDA). This Airfoil presents a high lift-to-drag ratio and a delayed stall angle with respect to the original FX-63-137 Airfoil, making it suitable for vertical-axis wind turbine applications. The practicality of JavaFoil for the comparison of different Airfoil geometries has been verified, as it is capable of obtaining results for a wide number of flow conditions in small computational times and with a user-friendly interface. Nevertheless, the results diverge from the actual solution for high angles of attack (beyond stall).
Joaquim R. R. A. Martins - One of the best experts on this subject based on the ideXlab platform.
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aerodynamic Shape optimization of wind turbine blades using a reynolds averaged navier stokes model and an adjoint method
Wind Energy, 2017Co-Authors: Tristan Dhert, Turaj Ashuri, Joaquim R. R. A. MartinsAbstract:Computational fluid dynamics (CFD) is increasingly used to analyze wind turbines, and the next logical step is to develop CFD-based optimization to enable further gains in performance and reduce model uncertainties. We present an aerodynamic Shape optimization framework consisting of a Reynolds-averaged Navier Stokes solver coupled to a numerical optimization algorithm, a geometry modeler, and a mesh perturbation algorithm. To efficiently handle the large number of design variables, we use a gradient-based optimization technique together with an adjoint method for computing the gradients of the torque coefficient with respect to the design variables. To demonstrate the effectiveness of the proposed approach, we maximize the torque of the NREL VI wind turbine blade with respect to pitch, twist, and Airfoil Shape design variables while constraining the blade thickness. We present a series of optimization cases with increasing number of variables, both for a single wind speed and for multiple wind speeds. For the optimization at a single wind speed performed with respect to all the design variables (1 pitch, 11 twist, and 240 Airfoil Shape variables), the torque coefficient increased by 22.4% relative to the NREL VI design. For the multiple-speed optimization, the torque increased by an average of 22.1%. Depending on the CFD mesh size and number of design variables, the optimization time ranges from 2 to 24h when using 256 cores, which means that wind turbine designers can use this process routinely. Copyright © 2016 John Wiley & Sons, Ltd.
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Aerodynamic Design Optimization Studies of a Blended-Wing-Body Aircraft
Journal of Aircraft, 2014Co-Authors: Joaquim R. R. A. MartinsAbstract:The blended wing body is an aircraft configuration that has the potential to be more efficient than conventional large transport aircraft configurations with the same capability. However, the design of the blended wing is challenging due to the tight coupling between aerodynamic performance, trim, and stability. Other design challenges include the nature and number of the design variables involved, and the transonic flow conditions. To address these issues, a series of aerodynamic Shape optimization studies using Reynolds-averaged Navier–Stokes computational fluid dynamics with a Spalart–Allmaras turbulence model is performed. A gradient-based optimization algorithm is used in conjunction with a discrete adjoint method that computes the derivatives of the aerodynamic forces. A total of 273 design variables—twist, Airfoil Shape, sweep, chord, and span—are considered. The drag coefficient at the cruise condition is minimized subject to lift, trim, static margin, and center plane bending moment constraints. ...