The motion of a helical vortex and the movement of the fluid particles along its axis are analyzed. The same form of the helical axis of the vortex and the trajectory of the particles sometimes leads to a false assumption of equality of these two different motions. The correct identification of both motions, however, is essential when considering the helical vortices in the wakes of rotors, or the displacement of the core of helicoidal tornado, etc. Only the same helical shape is the vortex axis and the streamline of the fluid particles can mistakenly merge these two different motions as the identical travel. We describe an experiment that clearly separates these two motions for the case of a stationary helical vortex, along the axis of which the fluid particles intensively move. The result shows that the absolute velocity of fluid particles does not coincide with the motion of the helical vortex as a whole.

分析了螺旋旋涡的运动和流体粒子沿其轴线的运动。涡旋螺旋轴和粒子轨迹的相同形式有时会导致这两种不同运动相等的错误假设。但是，在考虑转子尾流中的螺旋涡旋或螺旋龙卷风核心的位移等因素时，正确识别这两种运动至关重要。涡旋轴和流体粒子的流线只有相同的螺旋形状会错误地将这两个不同的动作合并为相同的行程。我们描述了一个实验，该实验明确地将两个运动分开，对于一个固定的螺旋涡流，沿着该涡旋的轴线，流体粒子集中运动。