In addition, the unsteady flowfiled of fan almost have transited to steady one when the rotation cycles more than 5 after startup.

• 而无论是钻孔或挖槽，其深度愈大对于性能与噪音之改善效果较明显。再者，当风扇开始转动至第5圈以上时，其流道之速度与压力分布趋势皆与稳态者相符，且其流量值并已达稳态值之95%25以上，而由暂态趋近于稳态。