Analysis of airflow through experimental rural buildings: Sensitivity to turbulence models

Full-scale experimental data and computational fluid dynamics (CFD) methods are used to determine the accuracy of four different turbulence models [standard k–ε, k–ε renormalisation group (RNG), k–ε realisable, Reynolds stress model (RSM)], which are used to describe the turbulent part of air in problems concerning the natural ventilation of buildings. Ventilation rates were measured in a livestock building using the decay tracer gas (CO2) technique. Airflow and temperature patterns were mapped out in a greenhouse with a tomato crop using a three-dimensional sonic anemometer and a fast-response temperature sensor. A commercially available CFD code was used to evaluate the different turbulence models. Average values from experiments were used for boundary conditions. The numerical results are compared with the experimental data, and they showed a good agreement, especially when the k–ε RNG turbulence model was used. The computations of the flow field using the different turbulence models showed noticeable differences for computed ventilation rate, air velocity and air temperature confirming the importance of the choice of the closure model for turbulence modelling.