Journal: Computers and Electronics in Agriculture
Author: Se-Woon Hong, Vasileios Exadaktylos, In-Bok Lee, Thomas Amon, Ali Youssef, Tomas Norton, Daniel Berckmans
Abstract
To study natural ventilation for agricultural buildings, OpenFOAM, an open source CFD code, enables to
develop tools that automate complex simulation procedures for nonprofessional CFD users. Prior to
developing such tools, this paper investigates the accuracy of simulated air velocity in three test buildings
according to different mesh sizes and turbulence models. The computed results, that were obtained using
13 different mesh sizes and 4 different k-e turbulence models, were qualitatively and quantitatively compared
to wind tunnel measurements by two validation metrics. The results showed that the smaller mesh
size leads to slightly higher simulation accuracy, but an increase in the number of meshes above a certain
level did not improve the simulation accuracy due to the problem of solution convergence. The mesh size
larger than 0.25 m at building walls was appropriate for the standard k-e model and the RNG k-e model,
while a small mesh size of 0.125 m was preferable for the low Re k-e model. The simulation results, especially
obtained from the RNG k-e model, were highly influenced by whether the solution converged
showing the relative error of on average 6.4% higher in the oscillatory solutions, while those from the
low Re k-e model were more dependent on the mesh size.
Keywords : Agricultural building, Computational fluid dynamics, Mesh size independence, Natural ventilation, OpenFOAM
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https://doi.org/10.1016/j.compag.2017.03.022