Abstract:
The north wall of solar greenhouses is often designed to be very thick with a slope on the outside. Heat preservation and storage can be achieved in the solar greenhouses in most areas of northern China during autumn and winter, where the dominant wind direction is the north or northwest. This study aims to clarify the influence on the roof wind pressure coefficient and wind load shape coefficient, due to the dip angle change of the outer north wall of the solar greenhouse. The numerical simulation was carried out to determine the distribution pattern of surface wind pressure on the solar greenhouse under different north wall outer inclination angles. Both the north and northwest winds were considered under computational fluid dynamics. The results show that: 1) The negative wind pressure coefficients were observed on the front and the upper half of the rear roof under the north and northwest wind. The wind suction was concentrated at the ridge and two edges (east and west) of the roof. The absolute value of the wind pressure coefficient of the upper front and the rear roof decreased significantly with the decrease of the camber of the north wall. 2) The wind load partitions of the north wall and roof of the greenhouse were refined to determine the partition wind load shape coefficients under different wind directions and different north wall dip angles. Once the north wind appeared, the absolute value of the upper shape coefficient of the front roof decreased by 16%-26% with the decrease of the north wall angle. Meanwhile, the absolute value of the lower shape coefficient of the front roof increased by 6%-57% with the decrease of the north wall camber. The absolute value of the shape coefficient of the east and west edges of the rear roof decreases by 62% and 66%, and the shape coefficient of the middle section of the rear roof changes from negative to positive. 3) Once northwest wind appeared, the absolute value of the shape coefficient of the upper part of the front and the rear roof was larger at the west end than the east end, while the absolute value of the shape coefficient of the lower part of the front roof was larger at the middle than at the both ends. With the camber of the north wall decreasing the absolute value of the shape coefficient of the middle and west section of the rear roof can be reduced by 30%-38%, meanwhile, those in other areas of the roof has no significant change. The dip angle of the north wall can be expected to reduce the wind load on the roof and edges of the side frame structure. The cover of the roof should be strengthened in the wind resistance design.