Closure to “Discussion of ‘Two-Dimensional Compressor Cascades With Optimum Velocity Distribution Over the Blade’” (1975, ASME J. Eng. Power, 97, p. 110)

1975 ◽  
Vol 97 (1) ◽  
pp. 110-110
Author(s):  
J. Citavy´
Keyword(s):  
Velocity Distribution ◽  
Two Dimensional ◽  
Optimum Velocity

Design of Cascades for Incompressible Plane Potential Flows With Prescribed Velocity Distribution

1971 ◽  
Vol 93 (3) ◽  
pp. 321-331 ◽  
Author(s):  
W. Schwering
Keyword(s):  
Velocity Distribution ◽  
Surface Velocity ◽  
Two Dimensional ◽  
Blade Profile ◽  
Method Of Calculation ◽  
Potential Flows ◽  
Loss Coefficients ◽  
Optimum Velocity ◽  
Made In

A method of calculation in designing two-dimensional cascades with given velocity distribution is described. An iterative method of the solution for the integral equation to determine the coordinate function for the blade profile is presented. A parametric formulation for the surface velocity distribution is developed. Some design examples for deceleration cascades with given flow angles and prescribed velocity distribution are discussed. Calculations of the boundary layers along the surfaces of the airfoil and cascade loss coefficients are made in order to obtain information on the quality of cascades designed by this method. Proceeding from the results of boundary layer calculations, it should be possible to further improve the parametric formulation for the surface velocity distribution and in this way prescribe better or even “optimum” velocity distributions.

Two-Dimensional Compressor Cascades With Optimum Velocity Distribution Over the Blade

1975 ◽  
Vol 97 (1) ◽  
pp. 101-109
Author(s):  
J. Citavy´
Keyword(s):  
Velocity Distribution ◽  
Two Dimensional ◽  
Suction Surface ◽  
Inverse Cascade ◽  
Pressure Distributions ◽  
Boundary Layer Method ◽  
Optimum Velocity ◽  
Stagger Angle ◽  
The Given

Results are presented of a research on an optimum cascade problem in two-dimensional subsonic flow at SVUSS (National Research Institute for Machine Design, Bechovice). The optimisation is based on a determination of the optimum velocity distribution (OVD) and on the solution of the inverse cascade problem. The OVD has been ascertained from a variational problem formulated by Sˇpacˇek as follows: to find such a velocity distribution on the suction surface for which the momentum thickness at the trailing edge has a minimum value. The problem was solved by Ru˚zˇicˇka using a simplified boundary layer method. Inverse cascade problem due to Pola´sˇek was employed to calculate the cascade geometry for a given optimum velocity distribution and the given stagger angle and the space chord ratio. Series of compressor cascades having the optimum velocity distributions has been designed by means of a digital computer. Some cascades of the series were tested in the low-speed windtunnel as well as at the high subsonic speeds. Reasonable agreement between the predicted and the experimental pressure distributions, flow deflection and loss coefficient has been achieved.

scholarly journals A Fast Two-Dimensional Numerical Method for the Wake Simulation of a Vertical Axis Wind Turbine

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 49
Author(s):  
Zheng Yuan ◽  
Jin Jiang ◽  
Jun Zang ◽  
Qihu Sheng ◽  
Ke Sun ◽  
...  
Keyword(s):  
Velocity Distribution ◽  
Numerical Method ◽  
Three Dimensional ◽  
Particle Method ◽  
Vortex Method ◽  
Vertical Axis ◽  
Two Dimensional ◽  
Vertical Axis Wind Turbine ◽  
Wake Effect ◽  
Array Design

In the array design of the vertical axis wind turbines (VAWT), the wake effect of the upstream VAWT on the downstream VAWT needs to be considered. In order to simulate the velocity distribution of a VAWT wake rapidly, a new two-dimensional numerical method is proposed, which can make the array design easier and faster. In this new approach, the finite vortex method and vortex particle method are combined to simulate the generation and evolution of the vortex, respectively, the fast multipole method (FMM) is used to accelerate the calculation. Based on a characteristic of the VAWT wake, that is, the velocity distribution can be fitted into a power-law function, a new correction model is introduced to correct the three-dimensional effect of the VAWT wake. Finally, the simulation results can be approximated to the published experimental results in the first-order. As a new numerical method to simulate the complex VAWT wake, this paper proves the feasibility of the method and makes a preliminary validation. This method is not used to simulate the complex three-dimensional turbulent evolution but to simulate the velocity distribution quickly and relatively accurately, which meets the requirement for rapid simulation in the preliminary array design.

Parameterization of dispersion in two-dimensional turbulence

2001 ◽  
Vol 439 ◽  
pp. 279-303 ◽  
Author(s):  
C. PASQUERO ◽  
A. PROVENZALE ◽  
A. BABIANO
Keyword(s):  
Velocity Distribution ◽  
Single Particle ◽  
Stochastic Models ◽  
Particle Dispersion ◽  
Turbulent Dispersion ◽  
Two Dimensional ◽  
Component Process ◽  
Velocity Autocorrelation ◽  
Coherent Vortices ◽  
Non Gaussian

We investigate the performance of standard stochastic models of single-particle dispersion in two-dimensional turbulence. Owing to the presence of coherent vortices, particle dispersion in two-dimensional turbulence is characterized by a non-Gaussian velocity distribution and a non-exponential velocity autocorrelation, and it cannot be properly captured by either linear or nonlinear stochastic models with a single component process. Based on physical and dynamical considerations, we introduce a family of two-process stochastic models that provide a better parameterization of turbulent dispersion in rotating barotropic flows.

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