Interactions between coherent structures and the urban canopy shear layer

The interaction between coherent structures and the canopy shear layer in urban areas is thought to be responsible for large heat and momentum transport across the canopy layer - roughness sublayer interface; however, the physics behind these interactions are still not fully understood. The spatial and temporal resolution of Direct Numerical Simulation (DNS) output is exploited to investigate potential flow structures in which these interactions take place, and also to explore appropriate detection algorithms of such structures. To this end, DNS time series data from individual grid points from within the DNS domain are then used to investigate how these mechanisms may manifest in observational data that are typically available with rather low spatial resolution. Observational data collected near roof-level of a street canyon in suburban terrain are then analyzed to see if signatures found in the DNS time series output also appear at full scale.