Modeling urban convection heat transfer by coupling Large eddy simulation with an energy balance model

Faithful modeling of convection heat transfer is a key step to guarantee the accuracy of energy balance terms in the urban environment which has implications for wall and roof conduction and building cooling load. However, most urban energy balance models for the atmospheric boundary layer (ABL) do not include a computational fluid dynamics (CFD) sub-model to dynamically compute the velocity field and convection heat transfer. Large eddy simulation (LES) with Immersed Boundary Method (IBM) as implemented at UCSD can provide velocity and temperature fields around any obstacle without changing the pseudospectral numerical method on the cartesian grid.

A simple energy balance model was implemented in the LES code. Numerical simulations of the flow over an urban canopy were carried out and validated with experimental data. Critical parameters such as convection heat transfer coefficients, surface temperature, and heat flux into buildings are examined.