Large-eddy simulation of marine hydrokinetic turbines

CFD simulation of marine hydrokinetic turbines using different turbine modeling approaches

Background

• Project: VFS Geophysics solver enhancement
• Marine hydrokinetic turbines require accurate CFD modeling to predict performance, wake characteristics, and environmental interactions in complex flow conditions.
• Key modeling approaches: actuator disk method, actuator line method, actuator surface method, and blade-resolved method using fluid-structure interaction (FSI).

Issues

• Selection of appropriate turbine modeling approach based on computational resources and accuracy requirements.
• Validation of different turbine models against experimental and field data.
• Comparison of computational efficiency versus accuracy trade-offs for various modeling approaches.
• Assessment of turbine wake prediction capabilities across different modeling frameworks.
• Development of guidelines for turbine model selection in various flow scenarios.

Contributions to the project

• Implementation of multiple turbine modeling approaches within large-eddy simulation (LES) framework.
• Comparative analysis of actuator disk, actuator line, and blade-resolved turbine models.
• Development of hybrid modeling approaches combining different levels of geometric detail.
• Validation studies against laboratory and field measurements for model accuracy assessment.
• Performance benchmarking of different turbine modeling approaches on HPC systems.

Implementing wave-current simulation into turbine modeling Frameworks

Background

• Project focus: Implementation of wave dynamics as inlet boundary conditions for turbulent current flow simulations
• Real ocean environments feature complex wave-current interactions that significantly affect turbine performance and loading conditions.
• Key physics concepts: Boussinesq and Grimshaw wave formulations, wave-current superposition, inlet boundary condition implementation, and dynamic turbine response.

Issues

• Implementation of Boussinesq and Grimshaw wave formulations as inlet boundary conditions.
• Accurate representation of wave kinematics and dynamics at the computational domain inlet.
• Ensuring smooth transition from wave-dominated inlet to wake-dominated regions downstream of turbines.
• Validation of wave boundary condition implementation against analytical and experimental solutions.
• Computational efficiency of wave boundary condition calculations during runtime.

Contributions to the project

• Development of inlet boundary conditions based on Boussinesq wave theory for shallow water applications.
• Implementation of Grimshaw formulation for more accurate nonlinear wave representation.
• Integration of time-varying wave boundary conditions with steady current profiles.
• Analysis of wave propagation accuracy and numerical dispersion characteristics.
• Assessment of turbine response under realistic wave-current inlet conditions.
• Validation studies comparing Boussinesq and Grimshaw formulations against experimental data.

Technical environment

• Computing: Linux HPC cluster, MPI, PETSc
• Programming: C/C++
• CFD Frameworks: VFS Geophysics
• Meshing: Fidelity Pointwise, Immersed Boundary Method (IBM)
• Visualization: ParaView, VisIt, Tecplot

This research advances the deployment of environmentally-compatible marine energy systems by understanding and mitigating the effects of natural waterway conditions on turbine performance.