When we open the nozzle of the tap slowly, we observe a fine near-transparent beam of water particles coming down smoothly. If we loosen the nozzle a bit more, rotational effects start to appear, which are more prominently visible at high velocities. Moreover, at high velocities, the water coming out appears completely opaque.

Can someone explain to me why this is so? Is this the effects of turbulence, or just unsteady flow? How does this happen?

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    $\begingroup$ Many kitchen and lavatory taps are designed to entrain air bubbles into the stream. The component that mixes the air with the water is called an aerator $\endgroup$ – Solomon Slow Sep 24 at 12:50

At higher speed, the turbulence allows for mixing of air with the stream, creating bubbles of air in the delaminated flow of water.

The changing refraction index causes reflections, giving the water its silvery sheen.

  • $\begingroup$ Thank you. What about the rotational effect in high velocity fluids? $\endgroup$ – PhysicsMonster_01 Sep 24 at 14:37

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