# How is static pressure measured?

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The pressure exerted by a liquid  or a gas is called as Static Pressure. The study of fluids revolves around the concept of static pressure. The term fluid here includes both liquids and gases, as both can flow. Static pressure along with the dynamic pressure defines the total pressure of the system and they are related as defined by the Bernoulli’s equation. Usually, the pressure that depends only on the fluid’s state and not on its motion is defined as static pressure. In fluid statics, the static pressure at any point is associated with the depth of that point in the fluid. In this field fluids at rest are studied. Thus the concepts of dynamic and total pressure don’t come into play in fluid statistics.

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### What is  static pressure?

Pressure is the amountofforce exerted ona unit area.  There are two kinds of pressures, the static pressure and dynamic pressure. Static pressure is the amount of pressure exerted by a non moving liquid  due to gravity. When there is a container filled with water, there is a static pressure exerted by the water on the bottom of the container because of gravity.

### What is static pressure?

Pressure is the amount of force exerted on a unit area. There are two kinds of pressures, the static pressure and dynamic pressure. Static pressure is the amount of pressure exerted by a non moving liquid due to gravity. When there is a container filled with water, there is a static pressure exerted by the water on the bottom of the container because of gravity.

### What is Bernoulli's Equation?

The field of science dealing with fluid in motion is known as Fluid mechanics. Here, the concept if total pressure of the fluid at any point comes into play which has two essential components namely static pressure and dynamic pressure. Dynamic pressure is due to the fluid’s state of motion. These two are related according to the Bernoulli’s equation. In simple words, Bernoulli’s equation is:

Static Pressure + Dynamic Pressure = Total Pressure

The actual equation is:
P + ½ ρv2 = P0, where,

• P is static pressure
• ρ is the fluid’s density
• v is velocity
• ½ ρv2 id the dynamic pressure
• And P0 is the total pressure

According to the Bernoulli’s equation, the total pressure remains constant along any streamline. However, great variations are observed in both static and dynamic pressure.

### What are the areas of application of the static pressure?

We are always dealing with fluids in our daily lives even though we seldom acknowledge their presence. The air and water are the most important of them. Thus the concept of static pressure is the key to many applications we come across from aviation to ventilation system. Aviation is the filed in which understanding the concept of static pressure plays a crucial role. The plane’s altimeter uses this concept to determine the altitude by measuring the air pressure at the height it is flying. In the field of architecture static pressure is the key concept to define and design the structure’s ventilation system. It determines the resistance of dust work and other components of the system against airflow. The knowledge of the static pressure is important even for the working of the fan as it has to overcome this pressure so as to work effectively. The mercury barometer is a good application of static pressure.

### How is static pressure measured and calculated?

Pressure can be measured using any of the many instruments designed for this purpose. The oldest of them is the mercury column. The more used and successful are the McLeod gauge, the Aneroid and the Bourdon gauge etc. usually, these instruments are used to measure the total pressure of the fluid. Static pressure is calculated using the Bernoulli’s theorem. The dynamic pressure can be determined by using the formula, P =½ ρv2.

• Here, ρ is the fluid density,
• v is the velocity of the fluid.

The value of dynamic pressure when subtracted from the total pressure as measured gives the static pressure.

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