Is the relationship between fluid velocity and pressure related to Einstein s theory of relativity?

Pressure and flow velocity are calculated by the following formulas:

Taking the commonly used free outflow of long pipes as an example, the calculation formula is h=(v 2*l) (c 2*r), where h is the water head, which can be converted by pressure, l is the length of the pipe, v is the flow rate of the pipe outflow, r is the hydraulic radius r = pipe section area inner wall perimeter = r 2, c is the Xie Cai coefficient c=r (1 6) n, n is the roughness, its size depends on the smoothness of the tube wall, and the smooth pipe to the dirty pipe is taken between to.

There is a "formula for calculating pressure and flow rate". There are some similar formulas in fluid mechanics, which have a lot of harsh conditions attached to them, and the scope of application is very small.

The pressure is not proportional to the flow velocity, and the pressure difference, pipe diameter, cross-sectional shape, whether there is a bend, the roughness of the pipe wall, and whether the viscosity properties of the isobore fluid ......, the relationship between pressure and flow rate cannot be determined.

If you want to ensure the flow rate, it is recommended that you install a flow meter and a control valve. Constant volume conveying can also be considered. For the fluid to flow, there must be a pressure difference (Note:

Not stress! However, the greater the pressure difference, the greater the flow rate. When you close the control valve down, you will notice that the pressure difference between the front and back of the valve is larger, but the flow rate is smaller.

The relationship between fluid flow velocity and pressure is as follows:

The greater the velocity of the fluid, the lower the pressure; The lower the flow velocity of the fluid, the greater the pressure. This effect was invented by Bernoulli, hence the name "Bernoulli effect". The Bernoulli effect is applicable to all fluids, including gases, and is one of the basic dissipation phenomena when a fluid flows steadily, reflecting the relationship between the pressure of the fluid and the flow velocity.

Fluid: <>

Liquids and gases are capable of flowing in addition to having a certain mass. They are collectively referred to as fluids.

Fluid pressure as a function of flow velocity.

Low pressure at high gas and liquid velocities; The pressure is strong at the position where the flow rate is small. This is the reason why the ships could not travel too closely.

The lift of the aircraft.

Due to the asymmetry of the shape of the wing cross-section, the oncoming wind is divided into upper and lower parts by the wing, and in the same time, the air flow above the wing passes a longer distance, the speed is larger, and the pressure on the wing is smaller; The lower air flow travels a shorter distance, the speed is smaller, and the pressure on the wing is greater, resulting in an upward lift.

The Bernoulli Effect:

In 1726, Bernoulli conducted numerous experiments and finally discovered the "boundary layer surface effect": as the fluid velocity increases, the pressure at the interface between the object and the fluid decreases, and vice versa. In honor of the scientist's contributions, the discovery is known as the "Bernoulli effect".

Bernoulli effect is applicable to all ideal fluids, including liquids and gases, and is one of the basic phenomena when the fluid flows steadily, reflecting the relationship between the pressure of the fluid and the flow velocity, and the relationship between the flow velocity and the pressure: the greater the flow velocity of the fluid, the smaller the pressure; The lower the flow velocity of the fluid, the greater the pressure.

p+1 2 v2 + gh=c, this equation is called Bernoulli's equation. where p is the pressure at a point in the fluid, v is the velocity of the fluid at that point, is the density of the fluid, g is the acceleration due to gravity, h is the height at the point, and c is a constant. Bernoulli's equation reflects the relationship between flow velocity and pressure, the greater the flow velocity of the fluid, the lower the pressure, and the smaller the flow velocity of the fluid, the greater the pressure.

Bernoulli's equation can also be expressed as p1+1 2 v12 + gh1 = p2+1 2 v22 + gh2. This is the basic principle adopted by hydraulics before the establishment of the theoretical equations of continuum in fluid mechanics, the essence of which is the conservation of mechanical energy of fluids. Namely:

Kinetic energy + gravitational potential energy + pressure potential energy = constant. The most famous corollary is that when the flow is at a constant height, the flow velocity is high, and the pressure is small.

It should be noted that since Bernoulli's equation is derived from the conservation of mechanical energy of machine grinding, it is only suitable for ideal fluids with negligible viscosity and non-compressibility. Boyou's Chunnooli's theorem has a wide range of applications in hydraulics and applied fluid dynamics. Moreover, because it is a finite relation, it is often used to replace the differential equation of motion, so it is also of great significance in the theoretical study of fluid mechanics.

There is a certain relationship between the pressure of the fluid and the flow velocity, which is given by Bernoulli's principle. Bernoulli's principle states that in an ideal fluid at rest, the total energy of the fluid, including kinetic and potential energy, remains constant along one of the streamlines of the fluid. At constant temperature and density, this law can be formulated as:

The higher the flow velocity, the lower the pressure. This law holds true in all directions of the fluid and can therefore be used to explain some phenomena.

For example, when water flows through a narrow part of a pipeline, the pressure of the missing liquid flowing along the pipe decreases due to the decrease in the cross-sectional area of the pipe, and when the liquid passes through the narrow section, the cross-sectional area increases and the flow velocity decreases, and the pressure of the liquid flowing along the pipe increases accordingly. This phenomenon can also be observed on the wings of airplanes and on the windshields of vehicles.

In flight, the upper surface curvature of the wing is greater and the lower surface curvature is smaller, and the faster the flight speed, the faster the upper surface flow velocity, the lower the pressure, and the slower the lower the surface flow velocity, the greater the pressure, thus forming lift. The design of the windshield also takes advantage of this principle, with its front part tilted to separate fluids, thereby reducing the resistance of airflow in front of the car, improving the speed and fuel efficiency of the car.