Evaluation of wind pressure acting on multi-span greenhouses using CFD technique, Part 1: Development of the CFD model

The CFD-computed and wind tunnel (WT)-measured wind pressure coefficients (Cp) were compared for development of CFD model. First, the y+ values were considered to identify the optimum conditions of the first cell height from the adjacent wall. The CFD-computed Cp values closely corresponded to the measured Cp values when the first cell height was 1.5 × 10−4 m. The computational domain test and the grid independence test were also conducted to determine the optimum domain size and mesh size. As a result of the computational domain test, the length of the upstream portion was fixed at 3H (H = ridge height), and the length of the downstream, side and upper portions were determined to be 15H, 5H and 5H, respectively. The mesh size was designed to be 1.0 × 10−2 m based on the grid independence test. Using the given design criteria, an appropriate turbulence model was selected, and the Shear stress transport (SST) k-ω model was eventually chosen as the turbulence model. Finally, the computed and measured Cp values were compared using statistical indices, demonstrating that the CFD-designed model could accurately compute the Cp values.