The Experts below are selected from a list of 4593 Experts worldwide ranked by ideXlab platform

Sandra Velardesuarez - One of the best experts on this subject based on the ideXlab platform.

  • an optimized Airfoil Geometry for vertical axis wind turbine applications
    International Journal of Green Energy, 2020
    Co-Authors: Andres Meanafernandez, Lorena Diazartos, J Fernandez M Oro, Sandra Velardesuarez
    Abstract:

    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...

  • proposal of an optimized Airfoil Geometry for vertical axis wind turbine applications
    2018
    Co-Authors: Andres Meanafernandez, Lorena Diazartos, Jesus Manuel Fernandez Oro, Sandra Velardesuarez
    Abstract:

    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).

Xin Zhang - One of the best experts on this subject based on the ideXlab platform.

  • an analytical correction to amiet s solution of Airfoil leading edge noise in non uniform mean flows
    Journal of Fluid Mechanics, 2020
    Co-Authors: Siyang Zhong, Xin Zhang, Bo Peng, Xun Huang
    Abstract:

    Gust/turbulence–leading edge interaction is a significant source of Airfoil broadband noise. An approach often used to predict the sound is based on Amiet’s flat-plate solution. Analytical studies have been conducted to investigate the influences of Airfoil geometries, non-uniform mean flows and turbulence statistics, which, however, were often too convoluted. In this work, the problem is revisited by proposing simple corrections to the standard flat-plate solution to account for the effect of non-uniform mean flows of real Airfoils. A key step in the method is to use a new space–time transformation that is analogous to the Prandtl–Glauert transformation to simplify the sound governing equation with spatially varying coefficients to a classical wave equation, which is then solved using the Schwarzschild technique as in Amiet’s solution. The impacts of Mach number, wavenumber and Airfoil Geometry on the prediction accuracy are investigated for both single-frequency and broadband cases, and the results are compared against high-fidelity simulations. It predicts the sound reduction by the Airfoil thickness, and reveals that the reduction is caused by the non-uniform streamwise velocity. The limitations of the model are discussed and the approximation errors are estimated. In general, the prediction error increases with the Airfoil thickness, the sound frequency and the flow Mach number. Nevertheless, in all cases studied in this work, the proposed correction can effectively improve the prediction accuracy of the flat-plate solution much more efficiently compared to numerical solutions of the Euler equations using computational aeroacoustics.

  • reduced dimension modeling of leading edge turbulent interaction noise
    AIAA CEAS Aeroacoustics Conference, 2014
    Co-Authors: James Gill, Xin Zhang, Phillip Joseph, Thomas Nodelanglois
    Abstract:

    A computational aeroacoustics approach is used to model the effects of real Airfoil Geometry on leading edge turbulent interaction noise for symmetric Airfoils at zero angle of attack. For the first time, one-component (transverse), two-component (transverse and streamwise), and three-component (transverse, streamwise, and spanwise) synthesized turbulent disturbances are modeled instead of single frequency transverse gusts, which previous computational studies of leading edge noise have been confined to. The effects of the inclusion of streamwise and spanwise disturbances on the noise are assessed, and it is shown that accurate noise predictions for symmetric Airfoils can be made by modeling only the transverse disturbances, which reduces the computational expense of simulations. Additionally, the two-component turbulent synthesis method is used to model the effects of Airfoil thickness on the noise for thicknesses ranging from 2% to 12%. By using sufficient Airfoil thicknesses to show trends, it is found that Airfoil thickness will reduce the noise at high frequency, and that the sound power P will reduce linearly with increasing Airfoil thickness.

  • symmetric Airfoil Geometry effects on leading edge noise
    Journal of the Acoustical Society of America, 2013
    Co-Authors: James Gill, Xin Zhang, Phillip Joseph
    Abstract:

    Computational aeroacoustic methods are applied to the modeling of noise due to interactions between gusts and the leading edge of real symmetric Airfoils. Single frequency harmonic gusts are interacted with various Airfoil geometries at zero angle of attack. The effects of Airfoil thickness and leading edge radius on noise are investigated systematically and independently for the first time, at higher frequencies than previously used in computational methods. Increases in both leading edge radius and thickness are found to reduce the predicted noise. This noise reduction effect becomes greater with increasing frequency and Mach number. The dominant noise reduction mechanism for Airfoils with real Geometry is found to be related to the leading edge stagnation region. It is shown that accurate leading edge noise predictions can be made when assuming an inviscid meanflow, but that it is not valid to assume a uniform meanflow. Analytic flat plate predictions are found to over-predict the noise due to a NACA 0002 Airfoil by up to 3 dB at high frequencies. The accuracy of analytic flat plate solutions can be expected to decrease with increasing Airfoil thickness, leading edge radius, gust frequency, and Mach number.

  • effects of real Airfoil Geometry on leading edge gust interaction noise
    AIAA CEAS Aeroacoustics Conference, 2013
    Co-Authors: James Gill, Xin Zhang, Phillip Joseph, Thomas Nodelanglois
    Abstract:

    High-order computational aeroacoustic methods are applied to the modeling of noise due to interactions between gusts and the leading edge of real symmetric Airfoils. The effects of Airfoil thickness and leading edge radius on noise are investigated systematically and in-dependently for the first time, at higher frequencies than previously used in computational methods. Single frequency harmonic gusts are interacted with Airfoils of varying Geometry at zero angle of attack. Increases in both leading edge radius and thickness are found to reduce the predicted noise. This noise reduction effect becomes greater with increasing frequency and Mach number. The dominant noise reduction mechanism for Airfoils with real Geometry is found to be related to the leading edge stagnation region. The assumption of uniform meanflow is shown to be invalid when modeling the leading edge noise of real Airfoils. However, accurate results are still obtained when an inviscid meanflow is assumed. The accuracy of analytic flat plate solutions can be expected to decrease with increasing Airfoil thickness, leading edge radius, gust frequency and Mach number.

Andres Meanafernandez - One of the best experts on this subject based on the ideXlab platform.

  • an optimized Airfoil Geometry for vertical axis wind turbine applications
    International Journal of Green Energy, 2020
    Co-Authors: Andres Meanafernandez, Lorena Diazartos, J Fernandez M Oro, Sandra Velardesuarez
    Abstract:

    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...

  • proposal of an optimized Airfoil Geometry for vertical axis wind turbine applications
    2018
    Co-Authors: Andres Meanafernandez, Lorena Diazartos, Jesus Manuel Fernandez Oro, Sandra Velardesuarez
    Abstract:

    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).

R Kelso - One of the best experts on this subject based on the ideXlab platform.

  • an insight into the dynamic stall lift characteristics
    Experimental Thermal and Fluid Science, 2014
    Co-Authors: Amanullah Choudhry, R R Leknys, Maziar Arjomandi, R Kelso
    Abstract:

    Abstract The article presents an insight into the dynamic stall lift characteristics through experimental work and a detailed survey of the seminal articles related to the phenomenon. Of particular interest is the dynamic stall observed on lifting surfaces as they undergo high-rate pitching motions at constant speeds up to a predetermined maximum angle of attack. The effects of several contributing parameters, such as the reduced frequency, Mach and Reynolds numbers of operation and the Airfoil Geometry, have been investigated. In addition, the behavior of the lift curve slope for an Airfoil undergoing constant pitch dynamic stall has been analyzed in detail to gain a better understanding of the mechanism for the unsteady case. The unsteady lift-curve has been broken down into stages and each stage has been analyzed separately. The aim is to obtain a deeper insight into the lift generation mechanism involved in unsteady motion of the Airfoil in order to improve the design of flow control techniques to exploit the dynamic stall process for a large range of applications.

Max J Miller - One of the best experts on this subject based on the ideXlab platform.

  • GT2004-53632 AN INTEGRATED DESIGN SYSTEM FOR FANS, COMPRESSORS AND TURBINES PART 2 -INTERACTIVE INTERFACE
    2020
    Co-Authors: Wolfgang A Sandel, Max J Miller
    Abstract:

    ABSTRACT A new, comprehensive, flexible, integrated design system for the aerodynamic design of fans, compressors, and turbines was developed during the past decade. It operates in both batch and interactive modes. The system contains a flow path generator, a through-flow solver, a stacked Airfoil Geometry generator, and a flank-milled Airfoil Geometry generator. This paper describes the interactive interface in more detail. In particular, it describes the design considerations, appearance, and functionality of the interactive interface. Top level requirements were established before the interface was designed. These requirements are explained and some of the key reasoning that drove the high level design of the interface is discussed. The four principal windows in the interface are described in detail. The interactive interface that was developed has significantly increased the productivity of fan, compressor and turbine aero designers

  • an integrated design system for fans compressors and turbines part 3 fan and compressor Airfoil Geometry generators
    ASME Turbo Expo 2004: Power for Land Sea and Air, 2004
    Co-Authors: Don F Durschmidt, Allen Medlock, Max J Miller
    Abstract:

    A new aerodynamic design system has been developed that includes Geometry generators for fans, axial compressors, and centrifugal compressors. This paper describes Geometry generators for both arbitrary and flank-milled Airfoils in axial, radial and mixed gas paths. Both Geometry generators have the special feature that Airfoil sections are constructed on construction curves, not on flow paths or streamlines. Construction curves are independent of flow path curves and streamlines, but can be defined to coincide with them. This makes high-flowing and low-flowing designs very easy. A special feature specific to the flank milled Airfoil Geometry generator is an undercutting analysis to reveal any unwanted contact with the conical cutter. This special feature and others have provided major savings from productivity improvements and reductions in design cycle time.Copyright © 2004 by ASME

  • an integrated design system for fans compressors and turbines part 2 interactive interface
    ASME Turbo Expo 2004: Power for Land Sea and Air, 2004
    Co-Authors: Wolfgang A Sandel, Max J Miller
    Abstract:

    A new, comprehensive, flexible, integrated design system for the aerodynamic design of fans, compressors, and turbines was developed during the past decade. It operates in both batch and interactive modes. The system contains a flow path generator, a through-flow solver, a stacked Airfoil Geometry generator, and a flank-milled Airfoil Geometry generator. This paper describes the interactive interface in more detail. In particular, it describes the design considerations, appearance, and functionality of the interactive interface. Top level requirements were established before the interface was designed. These requirements are explained and some of the key reasoning that drove the high level design of the interface is discussed. The four principal windows in the interface are described in detail. The interactive interface that was developed has significantly increased the productivity of fan, compressor and turbine aero designers.© 2004 ASME