Quan Hongchan's splash makes physics "non-existent". How do divers minimize the splash?

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According to CCTV reports, in the 2023 FINA Diving World Cup Montreal Station, the women's singles 10-meter platform focused duel. Quan Hongchan led the way all the way, winning four first places in the five moves in the competition, and got a full score of 99 points in 207C. In the end, she beat Chen Yuxi with 458.20 points to win the championship and become the double champion of this station.

What amazed netizens the most was her mastery of the "water splash disappearing technique", and they joked that physics is not applicable to the Chinese diving team.

Generally speaking, the faster the movement speed, the higher the splash. The faster the athlete enters the water, the higher the splash. The size of the athlete's body and the area of ​​contact between the athlete and the water surface are directly proportional to the size of the splash.

So the question is, how do divers reduce their contact with the water surface and minimize splashes when falling from a high diving platform?

This is directly related to the diving posture.

First of all, this is a problem of solid-liquid collision, which involves knowledge of fluid mechanics. When a wedge-shaped object enters the water, due to its incompressibility, the water body in contact will move in the direction of least resistance, that is, the direction of the slope where the wedge-shaped object contacts the water. The water body that is hit will jump out of the water, creating splashes. When a square object collides with the water surface, the water body that is hit will mainly move horizontally, and under the water pressure around it, it will not be able to jump out of the water.

When entering the water, the athlete will put one palm flat and grab the back of the hand with the other hand, which can keep the body stable while reducing the area of ​​contact between the body and the water. Although putting the hands together will reduce the contact between the palms and the water surface, it will bend the arms, increase the entry area of ​​the whole body, make the body trunk unstable, and make the subsequent movements floating.

Therefore, the splash caused by entering the water with flat palms is much smaller than the splash caused by entering the water with hands clasped together.

A qualified water splash action includes the following points:

1. Since the gravity of diving is 3-5 times the body weight, the legs must be clamped together when diving. When entering the water, the torso must be tight and straight, and every muscle in the body must exert force. If it is not tight, the impact when entering the water will push the body parts to deviate and produce large splashes.

2. Even if you are spinning and jumping in the air, and doing many difficult flips with your eyes closed, you must find the right time. Open your body to increase the moment of inertia, brake the rotation in time, tighten your hips, straighten your legs, make your body at a 90-degree angle to the water surface, and put your hands together in a prayer position to reduce resistance and make the splash smaller.

3. When entering the water, your arms need to clamp your head and be close to your ears. Your arms must be in the middle. If you enter the water forward or backward, the stability of your torso will be reduced. When entering the water, the water pressure will make your body arched.

One point that needs to be emphasized is that the zero splash standard does not mean no splash at all, but that the splash is very small and dissipates quickly.