GRE Question of the Day (June 9th)

Since turbines are designed without a(n) (i)____ understanding of such wind flows, they are failing at higher than expected rates. Failure to anticipate sudden gusts is especially (ii)____, because they can both damage the turbines and lead to sudden transmission line overloads. The situation is similar to the early days of aviation, when aircraft designers were working by (iii)____ because the atmosphere was so poorly understood.