Large Eddy Simulation of a Convective Boundary Layer

The atmospheric boundary layer (ABL) is the atmospheric region closest to the ground, where all the meteorological phenomena happen. Nowadays, its study, modelization and comprehension is important for several applications in many fields as meteorology, wind turbines, dispersion of pollutants and so on. This low region of the troposphere is governed and influenced by multiple phenomena affecting the behavior of the atmospheric boundary layer. Among these, one can cite the Earth’s rotation, the diurnal and spatial variations of surface heating, the water cycle (evaporation, clouds formation, precipitations), human activity (pollution) or the coexistence of convective and shear-generated turbulence. In particular, the heating of the surface creates thermal instabilities near the ground, generating convection cells. In this case, one can talk about convective atmospheric boundary layer (CABL). This master thesis follows a precedent one in which the author developed a model to simulate a free CBL using Large Eddy Simulation (LES). In order to improve the study and this LES model of the CABL, the aim of this thesis consists of adding an important concept that governs the ABL: the presence of wind and the associated Coriolis effect. In a first time, the Coriolis effect is implemented and validated in a reference case: a rotating channel. Then, a neutral atmosphere with wind is considered: the Ekman layer. After that, the case of a free CABL is considered to finally reach the goal of this thesis: a sheared CABL. Moreover, the impact of some variables such that the wind intensity and the ground heat flux is studied. Finally, results of these simulations are compared between each other and analyzed in order to draw some conclusions about the influence of these parameters on the behavior of the flow in the CABL.