Testing and Modeling Airborne Wind Energy (AWE) with hydrodynamic analogs

A long tradition in aerodynamics is using hydrodynamics as a “benchtop” testing basis. Because hydro-aero dynamic similarity applies at equivalent Re, a hydrodynamic tank or flume “water tunnel” is a ready means of realistic subscale testing. Velocimetry is easier to set up, and the equivalent time-base is slowed, facilitating observation. Hydro-aero is still a viable subscale testing methodology. In current Airborne Wind Energy (AWE) R&D, Dr. Chris Vermillion’s Lab at UNC tests in a flume-tank, including an MIT-originated AWE system (AWES) concept.

NREL’s OpenFAST contains a suite of Mooring Sim tools (MoorDyn, MAP, OrcaFlex, etc.) whose hydrodynamic engineering cases closely resemble AWE Kite Network concepts analytically predicted to operate at GW-rated unit-plant scale. KiteFAST is an OpenFAST component that so far only models GoogleX’s “Energy Drone” archetype. By incorporating OpenFAST Mooring tools with AeroDyn, KiteFAST can be greatly extended to AWES architectures known as “Rag & String”, encompassing basic power kites of polymer fabric and lines and many-connected Kite Networks of many kites and lines.

A low fidelity KiteFAST rag & string model based on Mooring sims could soon be exploring GW-scale Kite Network AWES potential, to provide early numeric validation. Longer-term, KiteFAST can upgrade to ExaWind (exaflop supercomputing) fidelity, for critical-path OpenFAST processing of complex multi-physics of dynamically-similar Floating Offshore HAWT Mooring Networks.