Numerical Framework for Marine/Offshore Applications
Our group has developed high-fidelity computational framework for multiphase fluid dynamics and fluid-structure interaction (FSI) simulations in marine and offshore engineering applications. Additional techniques implemented include interface-capturing level-set method for free-surface motion, that may include wave breaking and other topological changes, homogeneous mixture model for turbulent cavitating flows, efficient and robust coupling strategies and scalable HPC implementation. The stabilized and multi-scale formulation is used for the fluid mechanics and level-set equations. The underlying numerical formulation globally conserves mass and preserves a sharp air–water interface for the entire length of the simulation.
Computational fluid dynamics simulation of multiple full-scaled vertical-axis hydrokinetic turbines.
Computational fluid dynamics simulation of INSEAN E779A Propeller. Left to right: vorticity isovolumes colored by the velocity magnitude; vapor volume fraction isovolumes; experimental imaging.
Simulation of the effect of turbulence on the performance of vertical-axis hydrokinetic turbine from NewEnergy Corporation Inc. The synthetic turbulence generation is implemented in VMS framework. Left-Top: the actual system, where turbine is installed on a floating barge; Left-Bottom: computational model of the original turbine design (left) and modified configuration (right). Three columns represent the time-averaged streamwise velocity, instantaneous vorticity and vorticity isovolumes colored by velocity magnitude. Turbulence has a significant effect on power production and wake recovery which is investigated in a paper in details.
Simulation of the vertical-axis hydrokinetic turbine under the free-surface, different submerge depth and with different blade-struts configuration. The turbine is 25kW EnviroGen system from the NewEnergy Corporation Inc.
For FSI problems, an advanced structural modeling techniques based on Isogeometric Analysis (IGA) is employed. The bending-stabilized cable formulation is used to model mooring cables. The framework is suitable for accurate prediction of wave loading on a structures (submarine, ships, floating platforms, etc), prediction of the onset and development of cavitation on hydrofoils and propellers, simulation of turbine arrays (layout optimization and wake-structure interaction), stability analysis under different sea conditions, parametric optimization, air-wave-structure interaction.
Hydrodynamic simulation of Mirage Drive propulsion system based on two oscilating flexible foils (Collaboration with Hobie Cat).
Free-surface hydrodynamic simulation of tidal stream turbine in Airy waves.