In 1726, Bernoulli discovered the "boundary layer surface effect" through countless experiments: when the fluid velocity increases, the pressure on the interface between the object and the fluid will decrease, and vice versa. To commemorate this scientist's contribution, this discovery is called "Bernoulli effect". Bernoulli effect is applicable to all fluids, including gas, and it is one of the basic phenomena when fluid flows stably, reflecting the relationship between fluid pressure and flow rate, and the relationship between flow rate and pressure: the greater the flow rate of fluid, the smaller the pressure; The smaller the flow rate of the fluid, the greater the pressure.

For example, there is a steady flow of fluid in the pipeline, and the height of the liquid column in the vertical open thin tube at different cross sections of the pipeline is different, which shows that in the steady flow, the pressure is small where the velocity is large and the pressure is strong where the velocity is small. This phenomenon is called Bernoulli effect. Bernoulli equation: p+ 1/2pv 2 = constant.

There is a safety line on the railway station platform. This is because when the train comes at high speed, it will drive the air near the train carriage to move and the pressure will be reduced. If the passengers on the platform are too close to the train, there will be obvious pressure difference between the front and back of the passengers, which will lead to the passengers being attracted to the train and being injured.

Application examples of Bernoulli effect: airplane wings, sprayers, carburetors of gasoline engines, and spinning balls in ball games.