Wind tunnel study of the interaction of two or three side-by-side pipe-framed greenhouses on wind pressure coefficients.

摘要

More than two identical pipe-framed greenhouses (referred to as "pipe houses" hereafter) are often arranged in parallel. The wind pressure distributions on the pipe houses are significantly affected by the distance d_p between them. This article investigates the effect of d_p on the distribution of wind pressure coefficients C_p on two or three pipe houses arranged in parallel, based on a wind tunnel experiment using 1:20 scale models of a typical pipe house. Focus was on a wind direction perpendicular to the ridgeline. The distance d_p varied from 0.25 H to 6 H, with H being the ridge height of the pipe house. The results indicate that the C_p distribution on the windward side of the first pipe house was similar to that for an isolated pipe house, while the C_p values on the roof and leeward wall were dependent on d_p. On the other hand, the C_p values on the second and third pipe houses were generally negative and significantly affected by d_p, in particular on the windward wall and roof. Very high suctions were induced on the leeward roof of the second pipe house near the ridge when the distance d_p was small. The suctions may be induced by the second separation of the reattached flow on the windward roof at the location of the ridge. The local drag and lift coefficients, C_D and C_L, on the central cross-section were also computed from the C_p distribution. The influence of the adjacent pipe houses on the C_D was significant, while the C_L was less sensitive to d_p.