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Frigus
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In Bernoulli's theorem I understood the gravitational potential and kinetic energy but I can't understand what is pressure energy.
jartsa said:Let's say a million liter water tank is pressurized by a "water tower" that consists of an one liter water bottle that is lifted to a 100 m height.
Now every liter in the big tank has pressure energy 1000 Joules. Right?
If we let any of those water liters out, its kinetic energy will be 1000 Joules.
After that one liter of water is let out, the rest of the water has no pressure energy.
Incompressible liquid's pressure energy is its pressure times its volume. The actual energy is not in the liquid, but somewhere else. If the amount of energy somewhere else is small, we may quite easily notice that the liquid does not have as much energy as it's pressure energy suggests.
If the amount of actual energy somewhere else is large enough, we may get an impression that the liquid actually contains an amount of energy that is the same as its pressure energy. For example if the aforementioned water tower was large enough, then letting those million liters out of the tank would release energy: million * 1000 Joules.
Let's say there is a horizontal narrow pipe in which water is flowing at high speed. That water has lot of kinetic energy. At one point the pipe turns upwards and starts becoming wider. The water starts losing speed and kinetic energy and gaining gravitational potential energy. The pressure of the water does not increase, the water just freefalls upwards. But the water can pressurize something after it has reached a high position. I mean like water in a water tower.When water slows down, its kinetic energy must become some other type of energy, pressure energy it can not become, because pressure energy is not energy in the same way as kinetic energy. The kinetic energy of the water may push a piston, or push a tall water column upwards, or something like that. Note the word "push" there, if liquid is pushing hard on something, then we say that the pressure of the liquid is large, right?Hemant said:Sir can you elaborate more,I can't understand what you want to say and please can you also tell me why pressure is more in water flowing through larger cross section area as compared to water flowing through smaller cross section area when horizontal height is same of pipe
Let's see what I was saying ... I guess I was saying that pressure energy is an impression ... an impression that fluid has energy: pressure * volume.Maybe a better answer to the question "what is pressure energy in Bernoulli's law" would be just: "it's pressure * volume"Hemant said:Sir can you elaborate more,I can't understand what you want to say
Pressure energy is a type of energy that is associated with the pressure exerted by a fluid. This energy is a form of potential energy, as it is stored within the fluid and can be converted into other forms of energy, such as kinetic energy.
Bernoulli's theorem states that in a fluid flow, the sum of the pressure energy, kinetic energy, and potential energy remains constant. This means that as the pressure energy increases, the kinetic and potential energies must decrease, and vice versa.
Pressure energy is an important component in Bernoulli's theorem because it helps to explain the relationship between pressure and velocity in a fluid flow. It also allows us to make predictions about the behavior of fluids in different situations.
In Bernoulli's theorem, pressure energy is calculated by multiplying the pressure of the fluid by its volume. This value is then compared to the kinetic and potential energy to determine the overall energy of the fluid flow.
Yes, pressure energy can be converted into other forms of energy, such as kinetic energy. This is demonstrated in situations where a fluid is forced through a narrow opening, increasing its velocity and converting pressure energy into kinetic energy.