free-air flow的用法和樣例：
例句
- Propeller fans are used to move free air within a room or through channels having low frictional resistance.
螺旋槳式風機通常用於房間內或通過風道時移動自由氣流時，產生微弱的摩擦阻力。 - This turbulence caused the flow pattern in the tunnel to be similar to the flow pattern in free air at a higher Reynolds number.
這種紊流使風洞內的流譜與在較高的雷諾數下自由氣流中的流譜相似。
