Seminário: Large-Eddy Simulation of Scalar Exchanges over Urban Canopies (and other Rough Surfaces): Physical and Computational Challenges

26/03/2019 - 14:00
Auditório 1 do IAG (Rua do Matão, 1226, Cidade Universitária)
O seminário do Departamento de Ciências Atmosféricas será apresentado pelo Dr. Elie Bou-Zeid (Department of Civil and Environmental Engineering, Princeton University, USA)
Understanding of the physical processes modulating the transport of scalars over rough walls, such as building arrays in cities, is essential for parameterizing these processes in coarser geophysical models. Since passive scalars, such as water vapor, are advected with the flow, broad similarity is expected between the widely-studied momentum transfer problem and its scalar counterpart. However, unlike momentum that is dominated by form drag over very rough walls, scalar transport must occur through the viscous exchanges at the solid-fluid interface. This results in transport dissimilarity, as well as in a continuous dependence on the Reynolds number. In this talk we will review the challenges posed by these physics to flow computations in cities, and how we can overcome them. The results point to the importance of matching the Reynolds number of the simulations to real-world values. The analyses also underline the importance and dissimilarity (momentum versus scalars) of the dispersive fluxes inside and right above the urban canopy.