This fire is not burning the ground fuels themselves like the litter or organic material in the soil but just on the surface, it's the movement of a fluid.

这火是像垃圾或土壤中的有机物质那样燃烧地面燃料本身，而是仅仅在表面上，这是流体的运动。

A substance that's not quite liquid or gas, known as supercritical fluid.

一是液体也是气体的物质， 称为超临界流体。

It's important to note that fluid ounces measure volume, not weight, unlike the regular ounce.

需要注意的是，流体盎司衡量的是体积，而是重量，这与常规盎司同。

At this point,   the principles defining crowd movement are closer to fluid dynamics than anything else.

此时，定义人群移动的原则更接近流体力而是其他任何东西。