scholarly journals Study on the Wake of a Miniature Wind Turbine Using the Reynolds Stress Model

Energies ◽  
2016 ◽  
Vol 9 (10) ◽  
pp. 784 ◽  
Author(s):  
Jianxiao Hu ◽  
Qingshan Yang ◽  
Jian Zhang
Author(s):  
Randall Jackson ◽  
Ryoichi S. Amano

Computational Fluid Dynamics (CFD) has become a staple in wind energy research and studies cover a broad range of topics including atmospheric wind profiles, airfoil design, wind turbine design, terrain effects, and wake dynamics. One of the most important aspects of applying CFD methods is the selection of a turbulence closure model when solving the Reynolds Averaged Navier-Stokes (RANS) equations. In this research, the Reynolds Stress Model (RSM) was applied to predict the wake turbulence and velocity profiles for a small scale, 3-bladed, horizontal-axis wind turbine (HAWT) using a commercial CFD software, Star CCM+. The wind turbine was modeled directly by discretizing the rotor and also using an actuator disc concept to simulate the rotor. Wind tunnel experiments were performed using hot-wire anemometry to measure the velocity deficit at various downstream locations. High speed images were also captured to examine qualitatively the wake and tip vortex dissipation created from an oil mist. The CFD results show the RSM turbulence closure model to be excellent in predicting the wake velocity and tip vortex structure when compared to experimental results.


AIAA Journal ◽  
1997 ◽  
Vol 35 ◽  
pp. 91-98
Author(s):  
Jiang Luo ◽  
Budugur Lakshminarayana

Author(s):  
David Roos Launchbury ◽  
Luca Mangani ◽  
Ernesto Casartelli ◽  
Francesco Del Citto

Abstract In the industrial simulation of flow phenomena, turbulence modeling is of prime importance. Due to their low computational cost, Reynolds-averaged methods (RANS) are predominantly used for this purpose. However, eddy viscosity RANS models are often unable to adequately capture important flow physics, specifically when strongly anisotropic turbulence and vortex structures are present. In such cases the more costly 7-equation Reynolds stress models often lead to significantly better results. Unfortunately, these models are not widely used in the industry. The reason for this is not mainly the increased computational cost, but the stability and convergence issues such models usually exhibit. In this paper we present a robust implementation of a Reynolds stress model that is solved in a coupled manner, increasing stability and convergence speed significantly compared to segregated implementations. In addition, the decoupling of the velocity and Reynolds stress fields is addressed for the coupled equation formulation. A special wall function is presented that conserves the anisotropic properties of the model near the walls on coarser meshes. The presented Reynolds stress model is validated on a series of semi-academic test cases and then applied to two industrially relevant situations, namely the tip vortex of a NACA0012 profile and the Aachen Radiver radial compressor case.


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