Marine Engineering: Beginner CFD Training Package — Ep 08
Darrieus Water Turbine: Vertical Axis, Dynamic Mesh
- Lesson
- 08
- Run Time
- 16m 17s
- Published
- Aug 6, 2026
- Category
- Marine
- Course Progress
- 0%
Description
This project uses ANSYS Fluent to simulate a Darrieus-type vertical axis water turbine (VAWT) submerged in flowing water, applying the Dynamic Mesh method to capture rotation driven by the surrounding flow — a relevant application in marine renewable energy and hydrokinetic power generation. Unlike wind-based VAWTs, this turbine extracts kinetic energy directly from water flow, with its rotational axis perpendicular to the flow direction. The three-bladed turbine rotates freely in response to the fluid forces acting on it, allowing its performance under water flow conditions to be evaluated.
Methodology
The 3D geometry is built in DesignModeler, consisting of a large computational domain containing a three-bladed Darrieus turbine (0.5 m blade height), with the turbine center positioned 3 m from the inlet, 10 m from the outlet, and 0.75 m from the top and bottom domain surfaces. The domain is meshed in ANSYS Meshing using a hybrid grid — unstructured around the turbine body and structured elsewhere — totaling 7,422,668 elements.
Water enters the domain at 1 m/s along the horizontal axis, with a pressure outlet at atmospheric conditions and symmetry conditions applied to the top and lateral surfaces. The turbine's rotation is captured using the Dynamic Mesh model, with a cylindrical sub-region isolating the turbine blades as rigid bodies. Rotational motion is defined with one degree of freedom (1-DOF), using a blade mass of 1 kg and moment of inertia of 3.09 kg·m². The simulation is run transient, over 50 seconds with a 0.05 second time step, consistent with the dynamic mesh approach.
Conclusion
Results include 2D contours of velocity, pressure, and turbulent kinetic energy, along with pathlines and velocity vectors on a plane through the turbine center. Turbine torque and other performance characteristics are also analyzed, providing insight into the turbine's power extraction behavior — relevant to marine hydrokinetic energy system design and evaluation.