HAWT and VAWT Comparison: Moving Mesh Vs. MRF

HAWT and VAWT Comparison, (Mesh Motion and MRF)

Description

This project provides a detailed comparison of modeling techniques for two distinct wind turbine designs — Horizontal Axis Wind Turbines (HAWT) and Vertical Axis Wind Turbines (VAWT) — using ANSYS Fluent. Each turbine type is simulated using the CFD approach best suited to its rotational behavior: VAWT is modeled using Mesh Motion, while HAWT is modeled using the Moving Reference Frame (MRF) method, offering a direct, practical comparison of both techniques applied to two genuinely different turbine geometries.

Methodology

The VAWT simulation uses dynamic mesh motion, physically rotating the mesh to capture the turbine's motion through the domain, run as a transient analysis to resolve the time-dependent flow phenomena characteristic of vertical axis turbine operation, with an interface boundary defined between the rotating and stationary mesh zones.

The HAWT simulation instead applies the MRF technique, treating the surrounding fluid as rotating relative to the blades rather than physically moving the mesh, configured as a steady-state simulation for greater computational efficiency — reflecting the inherent trade-off between MRF's computational speed and Mesh Motion's higher temporal accuracy for capturing unsteady rotational effects.

Key performance metrics — lift, drag, and moment coefficients — were extracted for both turbine types, along with power output and overall efficiency, enabling a direct aerodynamic comparison between the two designs.

Conclusion

The results reveal the distinct flow patterns characteristic of each turbine design, along with the relative strengths and limitations of each configuration. This comparison also clarifies when each simulation method is most appropriate: Mesh Motion suits cases like VAWT, where blade angle of attack continuously changes throughout rotation and unsteady effects are central to the physics, while MRF suits cases like HAWT, where the flow field around the rotor is more consistently steady, allowing faster computation without significant loss of accuracy.

Together, these results offer practical guidance for selecting the appropriate simulation method based on turbine type and required accuracy, as well as insight into blade design optimization and how varying wind conditions affect performance across both HAWT and VAWT configurations.