  The near-wake of a vertical-axis cross-flow turbine (CFT) was modeled
numerically via blade-resolved $k$-$\omega$ SST and Spalart-Allmaras RANS
models in two and three dimensions. Results for each case are compared with
experimental measurements of the turbine shaft power, overall drag, mean
velocity, turbulence kinetic energy, and momentum transport terms in the
near-wake at one diameter downstream. It was shown that 2-D simulations
overpredict turbine loading and do not resolve mean vertical momentum
transport, which plays an important role in the near-wake's momentum balance.
The 3-D simulations fared better at predicting performance, with the
Spalart-Allmaras model predictions being closest to the experiments. The SST
model more accurately predicted the turbulence kinetic energy while the
Spalart-Allmaras model more closely matched the momentum transport terms in the
near-wake. These results show the potential of blade-resolved RANS as a design
tool and a way to "extrapolate" experimental flow field measurements.
