Energetic Large-Scale Structures found in Urban-type Boundary Layers

Flow through a complex environment typical of that found in urban boundary layers is investigated. MAVs maneuvering through an urban field are particularly susceptible to the turbulence encountered in these complex flows. We will present results describing the energetic large-scale coherent structures that are of interest to the aerodynamics community for the purpose of designing the next generation of MAVs. Experimentally we have used SPIV to fully characterize the mean 3D structures as well as investigate various flow regimes encountered in typical urban environments. Various coherent structures that are a function of the geometry of the modeled urban area as well as the incidence angle of the incoming wind direction will be presented and compared with the numerical simulations shown by Kandala et al. An attempt to quantify more accurately the size, location and strength of these structures will be presented.