Turbulent models for optimal control of Urban Heat Island Dynamics

Climate in urban areas differs from that in neighboring rural areas, as a result of urban development. It can create issues. Among theses disturbances, Urban Heat Island (UHI) is a huge risk with many negative consequences (health, comfort,...). It concerns urbanized area where temperatures are higher than in surrounding areas. To reduce this effect, the implantation (and design) of green spaces in dense cities is a pertinent solution.

In this study, we use optimal control method to find the optimal shape of green space. It is based on non stationnary turbulent Navier Stokes Forchheimer model coupled with heat equation considering building/soil radiation effects. The urban airflow is a turbulent flow through, around and over groups of porous building clusters. As a consequence, the choice of the turbulent model is very important. We will compare RANS k-ε and RNG k-ε models written for porous media. We compute two-dimensional direct numerical simulation. We show the results for temperature and velocity fields. This work presents the governing equations, the control optimal algorithm and discusses the results of the predictions of the flow problems constituting the initial validation space of the model.