流体在圆形水平直管中流动,测得平均流速为0.5m/s<img src="/lqwvjeImg/0c/0c4d0ee9586c24943632657b9648189e.png"style="width:56px;height:24px;">,压力降为<img src="/lqwvjeImg/18/185d771e14eb85f4a43d41285f218b8b.png"style="width:43px;height:20px;">。若将流速增加一倍,其他条件不变,则压强降变为( )。<br>·<img src="/lqwvjeImg/29/296c3216ec76c3dbaae81675a92ef49f.png"style="width:55px;height:25px;"><br>·<img src="/lqwvjeImg/02/02f6cca930a640f32f34d392aa8ad945.png"style="width:46px;height:25px;"><br>·<img src="/lqwvjeImg/bd/bda0f7877b26f48f4d79dadb42a7efe5.png"style="width:42px;height:23px;"><br>·<img src="/lqwvjeImg/3b/3b9ef68abf54ac2086634d7cb7c2155d.png"style="width:47px;height:22px;">