Numerical Simulation On Wind Pressure Of Arch-type Greenhouses

Greenhouses, also known as conservatory, are one of the most major agricultural facilities. Green houses groups are the most important representative of agricultural facilities in recent years. Compared with multiple rows of greenhouses, a single row of greenhouse has weak wind-resistance performance. It is not a rare scene that single rows of greenhouse will become flabby and even collapse under wind load. Currently, the research method towards wind load on the surface of greenhouse can be divided into four types: say filed measurement, wind tunnel test, wind engineering, and theoretical analysis, but the first two techniques not only can be very costly and time-consuming, but also be unable to make relatively reliable data to compare. Computational Fluid Dynamics, containing both practical and theoretical features, is one of the most efficient computer technologies to address the issue of liquid flow trend on a global scale. By using the CFD software platform, we can fully control the wind load information, and the distribution of wind pressure towards each greenhouse, thereby extracting data of coefficient of wind pressure and finding out the features of wind load on the surface of greenhouses, so that we are able to provide dependable basis and supports to optimize structure design and plan for greenhouses.This paper through the greenhouse structure wind load characteristics of domestic and foreign research situation and combining with the development of technology progress, introduces the CFD technology theory and calculation principle and application in the actual wind engineering method; The research object of the article is Greenhouse group circular arch type, in order to obtain under different wind Angle, the different distribution of circular arch type Greenhouse group each monomer air pressure coefficient and the size of the mutual influence between them, we choose can realize Realizablek-s model as the foundation to numerical wind simulation for greenhouse model; With a row of a group, double row of four groups, double row six groups, three rows of nine groups, four greenhouse configuration mode in the direction of the wind Angle of 0 °,45 ° and 90 °three directions are analyzed, the understanding of air pressure distribution, and compare the results of the calculation of the working condition of data. This article main research content and conclusions are as follows:1. Internal Greenhouse group in atmospheric boundary layer, the flow field flow situation will become very complex, and the direction of the imported to flow after the effect to the surface of the greenhouse, produces the backflow, discrete, effect of shunt and vortex flow. Of course in the process of analysis of the selection of CFD numerical simulation method, along with the ascension of computer hardware and efficient workability more show its economy, the advantages of high real restore ability, high reliability data.2.Circular arch type Greenhouse group in 12 kinds of working condition of simulation analysis show that 0 ° direction Angle and Angle of 90 ° direction type arch roof and side wall at the rear there will be a larger negative pressure value, affected by the suction is obvious; Wind direction Angle is 45 °, reflux will influence to the leeward side, pressure can by negative pressure into a positive pressure, and when the coming flow Angle is the most complicated conditions greenhouse surface subjected to wind, high air pressure region and the high gradient change region generally appear in the round arch roof and end of corner.3.Circular arch type Greenhouse group in different wind Angle and different group number, by the wind load of difference is very big, so we should according to the actual when the design, structure, economy, and the size of the wind speed, wind load coefficient factors to achieve its best suitability, stability and economy.