热带海岛串列圆拱形农业温室的风荷载干扰效应

Wind load interference effects on tandem arch-shaped agricultural greenhouses in tropical islands

  • 摘要: 农业生产中温室多呈阵列分布,而现有规范尚未充分考虑温室间风荷载干扰效应。本文开展串列布置下热带海岛圆拱形农业温室风洞测压试验,探究其风荷载干扰强度与机制、整体与局部体型系数及干扰因子。结果表明:受扰温室屋面风压干扰机制和强度受风向角与间距比共同影响,干扰强度随风向角呈“先增强后减弱”趋势,随间距比增大而减弱;干扰机制由小偏角的屏蔽效应转向中偏角的峡谷放大效应,约60°时干扰最为显著,进入大偏角后干扰减弱。单体温室屋面迎风区体型系数与现行规范偏差较大,而串列温室中受扰屋面迎风区仅在小间距比下与美国规范值偏差较小,屋顶区、背风屋面区体型系数均与欧盟规范值偏差较小,墙面体型系数与现有规范偏差均较大。受扰温室屋面局部体型系数随风向角呈交替的屏蔽与放大效应,迎风屋面各分区干扰效应最显著,屋顶次之,背风屋面最小;受扰温室靠近迎风山墙侧屋面边缘区局部不利体型系数干扰因子高达1.30,而屋面中部区、远离来流的山墙侧屋面边缘区局部不利体型系数干扰因子分别低至0.64、0.74。研究成果可为热带海岛农业温室结构的抗风设计与布局优化提供理论依据。

     

    Abstract: Greenhouses in agricultural production are mostly arranged in arrays, while existing codes have not fully considered the wind load interference effects between adjacent greenhouses. Wind tunnel pressure tests were conducted on tropical islands arch-shaped agricultural greenhouses arranged in tandem to investigate wind load interference intensity and mechanisms, overall and local wind load shape coefficients, and interference factors. The results indicate that the wind pressure interference mechanisms and intensity on the roof of the disturbed greenhouse are jointly influenced by the wind direction angle and spacing ratio. The interference intensity initially increases and then decreases with the wind direction angle, while it diminishes as the spacing ratio increases. The interference mechanism shifts from shielding at small deflection angles to the channeling amplification at medium deflection angles, reaching its most significant level at approximately 60°. Beyond large deflection angles, the interference weakens. For a single greenhouse, windward roof shape coefficients deviate substantially from current codes, whereas those of the disturbed windward roof shape coefficients show minor deviations from the U.S. code only at small spacing ratios. The shape coefficients for the roof area and leeward roof area align closely with European code values, while those for the wall surfaces exhibit significant deviations from existing codes. The local shape coefficients of the disturbed greenhouse roof exhibit alternating shielding and amplification effects with changing wind direction angles. The interference effect is most pronounced in the windward roof partitions, followed by the roof area, and least noticeable in the leeward roof area. The local unfavorable shape coefficient interference factor reaches up to 1.30 near the windward gable side edge of the roof, while it drops to as low as 0.64 in the central roof area and 0.74 at the roof edge away from the incoming flow side. These findings provide a theoretical basis for the wind-resistant design and layout optimization of agricultural greenhouse structures in tropical island regions.

     

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