An efficient solver for the RANS equations and a one-equation turbulence model

2011 ◽  
Vol 42 (1) ◽  
pp. 13-25 ◽  
Author(s):  
R.C. Swanson ◽  
C.-C. Rossow
Keyword(s):  
Turbulence Model ◽  
Rans Equations ◽  
Efficient Solver

Tall building influence on city wind pattern

2018 ◽  
Vol 29 (10) ◽  
pp. 1850086
Author(s):  
M. S. Almeida ◽  
A. D. Araújo ◽  
M. P. Almeida
Keyword(s):  
Population Growth ◽  
Numerical Simulations ◽  
Turbulence Model ◽  
Natural Ventilation ◽  
Tall Buildings ◽  
Navier Stokes ◽  
Urban Centers ◽  
Wind Pattern ◽  
Rans Equations ◽  
Weak Wind

The population growth in big urban centers generates the necessity for tall buildings. This phenomenon happens also in tourist regions where it is necessary to host many people. However, locations with high buildings interfere with the flow of the wind and can affect the comfort and safety of pedestrians at street level. Tall buildings barrier reduces the natural ventilation in regions far from the beach. This work presents the results concerning the effects created by tall buildings on Mucuripe beach, Fortaleza, Brazil. We performed numerical simulations to verify the wind interference with buildings in an area of [Formula: see text][Formula: see text]m2, using the OpenFOAM toolbox, to solve the Reynolds Averaged Navier–Stokes (RANS) equations with the [Formula: see text]–[Formula: see text] turbulence model. The results showed how the obstacles alter the airflow. From them, one can identify the regions with reduced safety and pedestrian comfort, and also the weak wind zone created by the downstream of the constructions for the different wind directions that are locally observed.

A comparative numerical study of four turbulence models for the prediction of horizontal axis wind turbine flow

2010 ◽  
Vol 224 (9) ◽  
pp. 1973-1979 ◽  
Author(s):  
N S Tachos ◽  
A E Filios ◽  
D P Margaris
Keyword(s):  
Wind Turbine ◽  
Turbulence Model ◽  
Numerical Study ◽  
Free Field ◽  
Turbulence Models ◽  
Horizontal Axis ◽  
Wind Condition ◽  
Computational Domain ◽  
Horizontal Axis Wind Turbine ◽  
Rans Equations

The analysis of the near and far flow fields of an experimental National Renewable Energy Laboratory (NREL) rotor, which has been used as the reference rotor for the Viscous and Aeroelastic Effects on Wind Turbine Blades (VISCEL) research program of the European Union, is described. The horizontal axis wind turbine (HAWT) flow is obtained by solving the steady-state Reynolds-averaged Navier—Stokes (RANS) equations, which are combined with one of four turbulence models (Spalart—Allmaras, k—∊, k—∊ renormalization group, and k—ω shear stress transport (SST)) aiming at validation of these models through a comparison of the predictions and the free field experimental measurements for the selected rotor. The computational domain is composed of 4.2×106 cells merged in a structured way, taking care of refinement of the grid near the rotor blade in order to enclose the boundary layer approach. The constant wind condition 7.2 m/s, which is the velocity of the selected experimental data, is considered in all calculations, and only the turbulence model is altered. It is confirmed that it is possible to analyse a HAWT rotor flow field with the RANS equations and that there is good agreement with experimental results, especially when they are combined with the k—ω SST turbulence model.

Analysis of Interference Effects of Adjacent Buildings on Wind Pressures

2013 ◽  
Vol 639-640 ◽  
pp. 489-492
Author(s):  
Ai She Zhang ◽  
Cui Lan Gao ◽  
De Qian Zheng
Keyword(s):  
Wind Tunnel ◽  
Turbulence Model ◽  
Navier Stokes ◽  
Experimental Investigations ◽  
Interference Effects ◽  
Rans Equations ◽  
Adjacent Buildings ◽  
Numerical Predictions ◽  
Adjacent Building ◽  
Wind Pressures

This paper presents numerical and experimental investigations of wind-induced interference effects on the pressure distributions on an adjacent building. The relative locations of the interfered building model and the interfering model are sited in staggered arrangement. The wind tunnel tests were carried out in a low-speed boundary layer wind tunnel. The numerical predictions for pressure distribution on the principal building are performed by solving the Reynolds-averaged Navier–Stokes (RANS) equations using the renormalization group (RNG) k–e turbulence model and then compared with the measurements. The RANS equations are solved by the pressure correction procedure of the SIMPLEC method. The simulated pressure, base force and base moment coefficients in different wind directions are generally in good agreement with the corresponding wind tunnel data. It is also found that the wind pressures, base forces and moments on the testing building are affected to some extent by the interference from adjacent buildings. The numerical simulation applying the SIMPLEC method using the QUICK upwind scheme and the RNG k–e turbulence model seems to be a useful tool for the predictions of wind pressures, and especially the wind forces acting on a building with an adjacent building.

Analysis and Modifications of Turbulence Models for Wind Turbine Wake Simulations in Atmospheric Boundary Layers

2016 ◽  
Author(s):  
Enrico G. A. Antonini ◽  
David A. Romero ◽  
Cristina H. Amon
Keyword(s):  
Flow Field ◽  
Wind Turbine ◽  
Reynolds Stress ◽  
Turbulence Model ◽  
Turbulence Models ◽  
Cfd Simulations ◽  
Rans Equations ◽  
Stress Models ◽  
Turbine Wake ◽  
Wind Turbine Wake

Computational Fluid Dynamics (CFD) simulations of wind turbine wakes are strongly influenced by the choice of the turbulence model used to close the Reynolds-averaged Navier-Stokes (RANS) equations. A wrong choice can lead to incorrect predictions of the velocity field characterizing the wind turbine wake, and consequently to an incorrect power estimation for wind turbines operating downstream. This study aims to investigate the influence of different turbulence models on the results of CFD wind turbine simulations. In particular, the k–ε, k–ω, SSTk–ω, and Reynolds stress models are used to close the RANS equations and their influence on the CFD simulations is evaluated from the flow field generated downstream a stand-alone wind turbine. The assessment of the turbulence models was conducted by comparing the CFD results with publicly available experimental measurements of the flow field from the Sexbierum wind farm. Consistent turbulence model constants were proposed for atmospheric boundary layer and wake flows according to previous literature and appropriate experimental observations. Modifications of the derived turbulence model constants were also investigated in order to improve agreement with experimental data. The results showed that the simulations using the k–ε and k–ω turbulence models consistently overestimated the velocity in the wind turbine wakes. On the other hand, the simulations using the SSTk–ω and Reynolds stress models could accurately capture the velocity in the wake of the wind turbine. Results also showed that the predictions from the k–ε and k–ω turbulence models could be improved by using the modified set of turbulence coefficients.

scholarly journals A high-order discontinuous Galerkin solver for the incompressible RANS equations coupled to the k−ϵ turbulence model

2020 ◽  
Vol 212 ◽  
pp. 104710
Author(s):  
Marco Tiberga ◽  
Aldo Hennink ◽  
Jan Leen Kloosterman ◽  
Danny Lathouwers
Keyword(s):  
Discontinuous Galerkin ◽  
Turbulence Model ◽  
High Order ◽  
Rans Equations
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