The slip velocities occur both in the vertical and horizontal directions in the influenced zone by the bottomoutlet.
在孔口影响域内，水沙两相不仅在垂向上有速度滑移，而且在水平方向上也有相对运动。
3
Usually a pipe, known as a dip leg, is connected to this bottomoutlet and, in catalytic cracking, serves to convey the solids back to the catalyst bed.