When flow velocity decreases below the corresponding incipient motion condition, no sediment movement occurs.

当水流速度小于相应的起始运动时，将无泥沙运动。

youdao

Test results show:for the same grain size groups the flow velocity relating incipient motion of these granite sand grains decreases as the bed slope increases;

实验结果表明，同一粒径组的非粘性花岗岩风化砂粒随底坡坡度的增加其起动流速变小；

youdao