The turbulent Leipzig Aerosol Cloud Interaction Simulator (LACIS-T) is a Göttingen-type moist-air wind tunnel designed for investigating interactions between turbulence and cloud microphysics under reproducible and well defined thermo- and fluid dynamic conditions. To draw reliable conclusions from measurements at the wind tunnel it is necessary to have precise knowledge about the flow field and turbulent fluctuations of velocity, temperature, and water vapour concentration. For this reason, the flow inside the measurement section of LACIS-T is simulated with OpenFOAM, employing a Large Eddy Simulation model for turbulence. Different boundary conditions for water vapour concentration and temperature are considered and the results are compared to measurements. Furthermore, particles are tracked through the domain using a Lagrangian approach. Thereto, a suitable growth model is implemented to calculate particle/droplet growth due to the condensation of water vapour from the gas phase. Joint work with D. Niedermeier, J. Voigtländer, and F. Stratmann.