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This work is focused on the optimal sizing of hybrid stand-alone photovoltaic–wind power systems from real hourly wind and solar irradiation data and electricity demand from a specific location. For optimization method photovoltaic panels, wind turbine and batteries specifications have been used. Using all these data and parameters in computer model HOMER, the minimization of the net present cost (NPC) or cost of unit of energy (COE) is obtained by selecting an appropriate hybrid stand-alone system configuration. [ABSTRACT FROM AUTHOR]

This paper has numerically analyzed the problem of enhanced the dynamic response of an electrohydrostatic actuators used in aerospace systems. Based on physical and mathematical model using both Matlab / Simulink and AMESim Software Student Edition some characteristics of this type of servo actuator were obtained. The results proved that a good tracking of reference is achieved and that the servo actuator meets very well the design requirements imposed in the time domain. [ABSTRACT FROM AUTHOR]

Nowadays, generation of renewal energies on-site are essentially to their optimum design configuration by achieving the extended final percentages of enhancement. This becomes a high necessity for accurate performance evaluation and incorporation of high-power computation in CFD strategies. The present work addresses to consolidate the Large Eddy Simulations in the integral design of buildings by aiming rigorous assessment of the flow field. Therefore, 3D steady RANS simulations are performed as an adaptation-based process of the building. The optimized geometry obtained thought the classical RANS approach is then used to demonstrate relevant design conditions and provide aerodynamics advantages to strengthen the local wind resource for forthcoming implementation of VAWT by means of LES. [ABSTRACT FROM AUTHOR]

The purpose of this paper was to determine the improvements that could be achieved by retrofitting a mobile winglet to a small airplane wing, taking into account only the aerodynamic effects (not considering the structural aspect). The CFD analysis is a crucial step in any conceptual design phase, as it provides reasonably accurate data before the experiments take place. Therefore, we performed numerical simulations for 9 winglet configurations and a test wing at 7 different angles of attack, considering a fully developed turbulent flow (Re ∼ 106) to see if and how substantial are the aerodynamic advantages. A NACA2412 airfoil was used as it is quite common for small airplanes used in pilot schools and for recreational flights. We chose the RANS model, combined with Realizable k-ε and SIMPLE algorithm as they have an acceptable computational cost and reasonable accuracy [ABSTRACT FROM AUTHOR]

The problem of proposing a framework for linear moment matching is tackled. It is possible to define notions of moments, i.e., from a complex "s-domain" approach and from a time-domain point of view. Based on these notions, reduced order models that achieve moment matching are obtained. This paper sets the basis to develop the theory of model reduction by moment matching for PDE (nonlinear) systems. [ABSTRACT FROM AUTHOR]

Currently all vehicle manufacturers are interested, from the earliest stages of design, obtaining optimized forms, especially reducing the drag force. This means a reduction in fuel consumption and also an improvement of stability characteristics of the vehicle. With the increasing computing power of computing machines, Computational Fluid Dynamics is the tool that can achieve these objectives and reduce phases of experimentation in wind tunnels. This study shows the benefits of using CFD to obtain shapes with lower drag. [ABSTRACT FROM AUTHOR]

Direct airfoil optimization with single or multiple objectives is always required in preliminary aircraft design. Low fidelity aerodynamic methods like incompressible potential and incompressible boundary layer are still attractive when used under a genetic algorithm that although is relatively slow, it enables the identification of the global solution while handling generic constraints in a simple way. The work is focused on small angles of attack, for flows without large separations, where the current low fidelity models provide a good level of certainty. Geometric parametrisation of airfoils considers NACA 4, generic polynomial and a combination of Class Shape for thickness and Bernstein polynomials for camber line. Few objective functions are tested and it is shown with numerical results that constraint optimization is fully consistent at high Reynolds, achieving solution uniqueness according to engineering requirements, while for low Reynolds there is a need for special treatment. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to evaluate the aerodynamic characteristics of a wing-disc, for a civil application in the fire-fighting system. The aerodynamic analysis is performed using a CFD code, named ANSYS Fluent, in the flow speed range up to 25 m/s, at lower and higher angle of attack. The simulation is three-dimensional, using URANS completed by a SST turbulence model. The results are used to examine the flow around the disc with increasing angle of attack and the structure of the wake. [ABSTRACT FROM AUTHOR]

This paper aims to achieve a practical study about the quality of the aerodynamic results provided by CFD simulation compared with the high level confidence of the experimental results. Numerical simulation were developed at low Reynolds Number, specific for a high lift airfoil. Some ideas and strategies have been issued for choosing a suitable turbulence model or a suitable low Reynolds airfoil for UAV's or a wind turbine blade. [ABSTRACT FROM AUTHOR]

In the last years the wind turbine with vertical axis (VAWT) began to be more attractive due benefits in exploitation, the power range covering usually the domain 2 kW-20 kW. But, VAWTs suffer from many complicated aerodynamically problems, of which dynamic stall is an inherent phenomenon when they are operating at low values of tip speed ratio (TSR < 4), and this has a significant impact on vibration, noise, and power output of the VAWTs. For this reason, in the present work we perform a computational investigation of a two-dimensional dynamic stall phenomenon around a NACA0012 airfoil in oscillating motion at relative low Reynolds number (∼105). The unsteady flow is investigated numerically using RANS approach with two turbulence models (k-ω SST and transition SST). The same analysis was performed to evaluate three flow control methods: two passive and one active. [ABSTRACT FROM AUTHOR]

A based method for modeling the aerodynamics of horizontal axis wind turbine has been developed. Circulation control is implemented by tangentially blowing a small high-velocity jet over a highly curved surface, such as a rounded trailing edge. This causes the boundary layer and the jet sheet to remain attached along the curved surface due to the Coanda effect and causing the jet to turn without separation. This analysis has been validated for the experimental data of a rotor tested at NASA Ames Research Center. Comparisons have been done against measurements for surface pressure distribution, force coefficients normal and tangential to the chord line, torque and root bending moments. This approach for enhancing the circulation around the airfoil sections (and hence L/D and power production) has been examined and found to produce useful increases in power at low wind speeds. [ABSTRACT FROM AUTHOR]

The trailing edge region of a single element wing fitted with Gurney flap has been studied. The complex flow separation phenomena on airfoils with Gurney flap at low Reynolds numbers have some specific features as the separation on set and reattachment locations and the streamline pattern. A detailed study shows the influence of the flap on the efficiency of the centrifugal compressor. [ABSTRACT FROM AUTHOR]

Most aerodynamic design tools for horizontal-axial wind turbines are based on the blade-element momentum theory (BEM). Due to the nature of this theory, the design tools need 2-D steady sectional lift and drag curves as an input. In practice, flow over a wind turbine rotor blade is neither two-dimensional nor steady, and is affected by rotation. Pioneering experiments have identified a consequence: at inboard rotor blade sections stall is delayed. This so-called Himmelskamp effect [1] gives a larger lift than predicted and, as a result, a higher power and loading than expected. Consequently, an aerodynamic model is needed to explain and predict sectional lift and drag under rotating conditions. [ABSTRACT FROM AUTHOR]

Information about a symposium on Mathematical Modeling and Numerical Analysis of Aerodynamic, Aeroelasticity and Noise for Wind Turbines is presented. Topics include the estimation of wind turbine performance, optimization of wind turbines, and the blade-tower coupling effect. The event also highlighted the design, aerodynamic and aeroelasticity characteristics estimation, and performance prediction of wind turbine using mathematical modelling and numerical analysis.