The Experts below are selected from a list of 210 Experts worldwide ranked by ideXlab platform

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

  • PERFORMANCE OF THE BIPLANE WELLS TURBINE
    Journal of Offshore Mechanics and Arctic Engineering, 1996
    Co-Authors: Luís M.c. Gato, R. Curran
    Abstract:

    The paper describes experimental investigation of the biplane Wells turbine for a wave power plant. Performance of the biplane turbine was investigated in unidirectional steady air flow by varying the model configuRations using solidity, gap to Chord Ratio and stagger angle. It was concluded that the performance of the biplane turbine is considerably influenced by inviscid and viscous flow effects. Adjacent upstream and downstream pressure distributions will either suppress or enhance one-another depending on stagger given sufficiently small G/c Ratio. The viscous effect from the upstream wake seems to defer stall by advancing boundary layer transition.

Eberhard Nicke - One of the best experts on this subject based on the ideXlab platform.

  • A Database of Optimal Airfoils for Axial Compressor Throughflow Design
    Journal of Turbomachinery, 2017
    Co-Authors: Markus Schnoes, Eberhard Nicke
    Abstract:

    Airfoil shapes tailored to specific inflow conditions and loading requirements can offer a significant performance potential over classic airfoil shapes. However, their optimal operating range has to be matched thoroughly to the overall compressor layout. This paper describes methods to organize a large set of optimized airfoils in a database and its application in the throughflow design. Optimized airfoils are structured in five dimensions: inlet Mach number, blade stagger angle, pitch–Chord Ratio, maximum thickness–Chord Ratio, and a parameter for aerodynamic loading. In this space, a high number of airfoil geometries are generated by means of numerical optimization. During the optimization of each airfoil, the performance at design and off-design conditions is evaluated with the blade-to-blade flow solver MISES. Together with the airfoil geometry, the database stores automatically calibrated correlations which describe the cascade performance in throughflow calculation. Based on these methods, two subsonic stages of a 4.5-stage transonic research compressor are redesigned. Performance of the baseline and updated geometry is evaluated with 3D CFD. The overall approach offers accurate throughflow design incorporating optimized airfoil shapes and a fast transition from throughflow to 3D CFD design.

  • A Database of Optimal Airfoils for Axial Compressor Throughflow Design
    Volume 2C: Turbomachinery, 2016
    Co-Authors: Markus Schnoes, Eberhard Nicke
    Abstract:

    This text describes methods to organize a large set of optimized airfoils in a relational database and its application in throughflow design. Optimized airfoils are structured in five dimensions: inlet Mach number, blade stagger angle, pitch-Chord Ratio, maximum thickness-Chord Ratio and a parameter for aerodynamic loading. In this space, a high number of airfoil geometries is generated by means of numerical optimization. Each airfoil geometry is tailored to its specific requirements and optimized for a wide working range as well as low losses. During the optimization of each airfoil, performance in design and off-design conditions is evaluated with the blade-to-blade flow solver MISES. Together with airfoil geometry, the database stores automatically calibrated correlations which describe cascade performance in throughflow calculation. Based on these methods, two subsonic stages of a 4.5-stage transonic research compressor are redesigned. Performance of baseline and updated geometries is evaluated with 3D CFD. The overall approach offers accurate throughflow design incorporating optimized airfoil shapes and a fast transition from throughflow to 3D CFD design.

Luís M.c. Gato - One of the best experts on this subject based on the ideXlab platform.

  • PERFORMANCE OF THE BIPLANE WELLS TURBINE
    Journal of Offshore Mechanics and Arctic Engineering, 1996
    Co-Authors: Luís M.c. Gato, R. Curran
    Abstract:

    The paper describes experimental investigation of the biplane Wells turbine for a wave power plant. Performance of the biplane turbine was investigated in unidirectional steady air flow by varying the model configuRations using solidity, gap to Chord Ratio and stagger angle. It was concluded that the performance of the biplane turbine is considerably influenced by inviscid and viscous flow effects. Adjacent upstream and downstream pressure distributions will either suppress or enhance one-another depending on stagger given sufficiently small G/c Ratio. The viscous effect from the upstream wake seems to defer stall by advancing boundary layer transition.

Ujjwal K. Saha - One of the best experts on this subject based on the ideXlab platform.

  • On the influence of blade thickness-to-Chord Ratio on dynamic stall phenomenon in H-type Darrieus wind rotors
    Energy Conversion and Management, 2020
    Co-Authors: Siddhant Jain, Ujjwal K. Saha
    Abstract:

    Abstract The present work examines the influence of blade thickness-to-Chord Ratio (t/c) on dynamic stall phenomenon in an H-type Darrieus wind rotor. A 2D incompressible numerical study is conducted on a single-bladed rotor at a tip speed Ratio (TSR) of 2 with a motivation to understand the intricate flow physics around the blade by employing a transitional shear stress transport (TSST) model. Five different t/c Ratios (9%, 12%, 15%, 18% and 21%) have been studied for symmetrical NACA airfoils. It is found that in case of thinner airfoils (t/c = 9% and 12%), the formation of the dynamic stall vortex (DSV) is preceded by the formation and bursting of leading edge (LE) laminar sepaRation bubble (LSB) leading to a more abrupt LE type stall. For t/c = 15%, a mixed type stall is observed with LSBs distributed over the airfoil resulting in two coherent vortex structures that subsequently merge to form the DSV. A trailing edge (TE) type stall was observed in case of thicker airfoils (t/c = 18% and 21%). The largest peak in the lift and drag coefficients (Cl, Cd) values of 1.87 and 1.27, respectively are obtained with the thinnest airfoil. However, the largest peak in the moment coefficient (Cm) value is achieved with t/c = 12%. Further, due to the DSV sepaRation at the lift stall point, a further increase of 6.3%, 7.1%, 1.5%, 8.94% and 11.8% in Cd values is observed for increasing order of t/c. Overall, the study sheds light on the capability of TSST model in capturing the dynamic stall phenomenon efficiently.

O.g. Mcgee - One of the best experts on this subject based on the ideXlab platform.

  • Natural vibRations of shear deformable cantilevered skewed trapezoidal and triangular thick plates
    Computers & Structures, 1992
    Co-Authors: O.g. Mcgee, Tarunjit S. Butalia
    Abstract:

    Abstract In a recent companion paper, the efficacy of higher-order shear deformable, C0 continuous, Lagrangian isoparametric plate finite element analyses has been demonstrated on cantilevered skewed (parallelogram) thick plates. The present work extends the method to include skewed thick plates having trapezoidal and triangular planforms, and is the first known vibRational study of such plates. Extensive and accurate nondimensional frequency tables and graphical charts are presented for a series of trapezoidal plates showing the effect of aspect Ratio, Chord Ratio, thickness Ratio, and skew angle. The need for the present higher-order shear deformable plate finite element method for skewed trapezoidal plate vibRations increases as the skew angle increases and as the aspect Ratio, Chord Ratio, and thickness Ratio decreases. Some theoretical and experimental data hitherto published for delta and skewed triangular cantilevered plates are compared with results obtained using the present finite element method. No published theoretical results for cantilevered skewed trapezoidal and triangular thick plates are known to exist.

  • VibRations of cantilevered skewed trapezoidal and triangular plates with corner stress singularities
    International Journal of Mechanical Sciences, 1992
    Co-Authors: O.g. Mcgee, Arthur W. Leissa, Chiung-shiann Huang
    Abstract:

    Abstract In a recent companion paper, the efficacy of admissible corner functions used in conjunction with mathematically complete polynomials has been demonstrated in an exhaustive amount of Ritz convergence tables apropos to cantilevered skew parallelogram plates. The present work extends the method to include skewed plates having trapezoidal and triangular planforms, and is the first known vibRational study encompassing the effect of bending stress singularities at the reentrant corner of such plates. Extensive and accurate nondimensional frequency tables and graphical charts are presented for a series of trapezoidal plates showing the effect of aspect Ratio, Chord Ratio and skew angle. The importance of using admissible corner functions in skew trapezoidal plate vibRations is found to increase as the skew angle increases and as the aspect Ratio and Chord Ratio decreases. Some theoretical and experimental data heretofore published for delta and skewed triangular cantilevered plates are compared with results obtained using the present method. No previous theoretical results for skewed trapezoidal cantilevered plates are known to exist.