Cfd modelling of h-darrieus vertical axis wind turbine

3
) 
Length (m) 
1.25 m (Turbine Radius)
Area (m
2
) 
2.5 m (Turbine Diameter) 
4.6.5 Solution Methods 
Several Fluent solver algorithms were examined, and the simulated parameters such as the moment 
coefficient showed little variation. However, the PISO Pressure- Velocity Coupling method was 
chosen based on the major guidelines provided in the Fluent Theory Guide [86] as Fluent 
recommends it for transient or unsteady simulations. 
In Fluent, the next step is to choose the Spatial Discretization methods: 

Gradient: For unstructured meshes, the Fluent Theory Guide advises using the Least Squares 
Cell Based method. 

Pressure: Second order method is used for transient simulations. 

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45 

Momentum: Instead of using First Order Upwind, which could provide a faster convergence, 
Second Order Upwind is employed for better accuracy. 

Transient Formulation: Second Order Implicit method was used for better results 
The remaining parameters are set to their default values in Fluent. 

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46 
4.6.6 Summary of the fluid domain simulation 
Table 8: Summary of the fluid domain simulation 
Geometry 
Airfoil
NACA 0015 
Turbine diameter D (m)
2.5 
Turbine radius R (m)
1.25 
Chord length c (m) 
0.4 
Number of blades 
3 
Solver 
Turbulence model
Transition SST 
Approach
Sliding Mesh 
Pressure-Velocity Coupling Scheme
PISO 
Gradient discretization
Least Squares Cell Based 
Pressure discretization
Second Order 
Momentum discretization
Second Order Upwind
Turbulent Kinetic Energy discretization
Second Order Upwind
Specific Dissipation Rate discretization
Second Order Upwind
Momentum Thickness Re discretization 
Second Order Upwind
Transient Formulation 
Second Order Implicit 
Reference values 
Free stream velocity V
∞
(m/s) 
10 
Density ρ (kg/m
3
) 
1.225 
Dynamic viscosity μ (kg/m · s) 
1.7894e-05 
Other parameters Time step
∆𝑡|
1°
Max. Iterations per time step 
60 
Number of time steps for 1 revolution 
360