Experiments on fire whirls generated by a gasoline pool fire in a vertical shaft were carried out. Vortex motions of swirling flame induced by buoyancy above the pool fires were observed to be more vigorous with increase in height. Upward flame motions were resulted due to increase in buoyancy. The phenomenon was described mathematically by solving the vorticity transport equation with reasonable assumptions and appropriate boundary conditions. Analysis gave swirling attenuation along the vertical direction. By measuring heat release rates and fire whirl diameters at different heights, vertical variation of circular speeds of fire whirls was derived.

中文翻译：

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火旋风在竖井中的涡旋运动衰减

对竖井中汽油池火灾产生的火漩涡进行了实验。观察到由池火上方的浮力引起的旋流火焰的涡旋运动随着高度的增加而更加剧烈。由于浮力的增加，导致向上的火焰运动。通过在合理的假设和适当的边界条件下求解涡度输运方程，对这一现象进行了数学描述。分析给出了沿垂直方向的旋流衰减。通过测量不同高度的热释放率和火旋风直径，推导出火旋风圆周速度的垂直变化。