The fact behind Hydrodynamic Levitation

Everyone must have played with water and ball. But do you know water and ball play with each other in a situation?

Welcome to Engineering Master. In this article we will discuss a wonderful concept of physics known as Hydrodynamic Levitation and find how a ball plays with water…

The ability to levitate a lightweight ball at top of a jet of water is known as Hydrodynamic Levitation. The ball is levitating in a very stable way. The setup was so stable that even stopping the water for a few seconds doesn’t t stop the ball to levitate.

But the question still arises how the ball is still like this?

The thing happens here is the stream contacts the ball and pushes the ball out, away from the stream. The ball actually will stay there. It is a stable configuration. The water is getting thrown over and down by the ball and since the ball is putting a force over and down on the water. That water is putting a force up and on the ball which keep it right in that stream. It is because there is a bit adhesion between water and ball.

Once the ball is levitating, it remains stable because if it drifts too far into the stream, that decreases the flow of water around the ball reducing the force pushing it into the stream and if it drifts too far out that increases the water flow over the ball increasing the force pushing it back into the stream that’s what makes the equilibrium position so stable.

In the case of levitating a disc, we need to keep it in the right orientation. Then the disc starts levitating. It is hard to levitate the disc than the ball because disc has to maintain the vertical orientation in order to levitate.
So finally, the concept involves getting the water jet to flow vertically. It runs up and over the ball/disc and it will create a stable equilibrium which allows it to levitate.

Gifs and picture credits- Veritasium (Youtube channel)