An experimental investigation of the near-wake region of a slender, propeller-driven model at pitch or yaw was undertaken in the Virginia Tech low-turbulence wind tunnel. The control surfaces on the model were set to render the model in equilibrium for the case with model pitch. The vehicle design was such that the vertical control surfaces were insufficient to achieve an equilibrium condition with the model at yaw. This is neither unusual nor undesirable, since such a vehicle can turn freely and there is little desire to operate in a straight line at yaw. A yaw-head probe was used for mean flow measurements, and a hot-wire anemometer with a normal, single wire or an X-wire served to obtain turbulent flow characteristics. The control surfaces were found to have mainly local influences on the flow field. In the pitch case, good symmetry was exhibited on both mean and turbulent flow quantities, but the lack of complete, all-directional equilibrium in the yaw case prevented the achievement of symmetry.
Spectral-Element Simulation of the Turbulent Flow in an Urban Environment