Analysis of Interactional Aerodynamics in Multi-Rotor Wind Turbines using Large Eddy Simulations

An alternative to traditional upscaling of single-rotor turbines for higher power production
is the use of multiple rotors mounted on the same tower. Such multi-rotor configurations have
been hypothesized to show improved wake recovery compared to area- and power-equivalent
single-rotors with no adverse effect on power production. Analysis of the aerodynamics of multirotor
configurations using dynamic large eddy simulations (LES) forms the focus of this work,
where an actuator line/block model is employed for the rotors to reduce the computational cost.
A stochastic turbulence generator is utilized to impose a fluctuating inflow velocity with no
associated shear in order to study the effect of incoming turbulence on shear layer breakdown
andwake recovery effects. The current results showan early onset ofwake recovery in the multirotor
configuration with a reducing velocity deficit as well as a higher degree of uniformity in
the wake compared to the single rotor simulation.