A Reduced Model Retaining 1st-Order Vortex Corrections in the Averaged Dynamics of the Wind past Buildings

The nonlinear dynamics of turbulence formed by the wind flowing near solid objects can be studied with a variety of different physical models, more or less numerically demanding. An application is the study of the formation of turbulence past buildings, with the goal of determining the no-fly zones for drones in smart cities. In this paper, we examine the Reynolds- averaged Navier-Stokes (RANS) Amodel, which is popular in simulating the wind dynamics in small portions of a city. We compare the results with those of the Large-Eddy- Simulation (LES) model, more physically comprehensive, but more numerically demanding. The analysis of the vortex formation in the LES model helps estimating the 1st-order correction to add to the lighter RANS results. This constitutes the scheme of a reduced model, which takes the RANS model as a basis, on top of which an extra layer of the dimension of the main vortex, obtained with the LES simulation, is added. This reduce model can be used, for example, to estimate the no-fly zone with a higher level of accuracy with respect to the pure RANS, Ayet with a computational effort comparable to the pure RANS.