单项选择题
Which of the following statements about flow meters is FALSE? 以下关于流量计的哪种说法是错误的? ( )
A.The Venturi meter has fixed cross section areas, but varying pressure drop; while rotameter is the opposite 文丘里管利用恒定的横截面积和变动的压降来测量流量;转子流量计则相反。
B.The Venturi meter cannot measure velocity distribution in a flow. 文丘里管无法测量流体的速度分布。
C.The Pitot tube cannot measure the overall rate of a flow. 皮托管无法测量流体的总流量。
D.The rotameter measures the overall flow rate. 转子流量计可以测量流体总流量。
E.In a rotameter, the float reaches equilibrium when drag force balances its gravity. 在转子流量计中,当转子达到平衡态时,它所受的曳力与重力相平衡。