2、某输油管道长L=500m,直径d=0.15m,流速v0.24m/s,油的粘滞系数v=2.0cm/s 2、某输油管道长L=500m,直径d=0.15m,流速v0.24m/s,油的粘滞系数v=2.0cm/s 发布时间:2025-03-20 06:51:57