Summary
We have conducted a wind tunnel test to obtain data on wind resistance for the design of vinyl-house. Two 1/20 scale models were used, one is a rigid model, the other is an elastic model, and the approch wind direction was normal to eaves side.HomePage
In the rigid model, we used three gable roof-models, one with angular eaves and ridge, the others with curved surface. We found that each distribution of wind pressure are similar among of the models except in the area close to the eaves. The wind force (lift and drag) on the whole model also appeared to be the same value.
In the elastic model, we have changed the opening position and the opening ratio and then measured tensile force of the pressed down rope, bending stress of the frame and internal pressure.
The result shows that the mechanism of wind resistance remarkably depends on the opening position, but not depend on the opening ratio. That is to say, when the opening is located on the windward side wall, the covering plastic film will expand and the internal pressure coefficient will become positive. But, in case of the opening is positioned downwind, the internal pressure coefficient become negative, and the shape of the covering plastic film has no change. The model which has no opening or the opening on the both sides shows that the internal pressure coefficientis almost zero.
Under strong wind, the change of the shape of the vinylhouse is strongly effective on the lift, the tensile force of pressed down rope and the bending stress of the frame.
With these results, we devised relevant data of wind resistance for the design of vinylhouses.