Does it matter if one uses gauge instead of absolute pressures in applying Bernoulli’s equation? Explain.

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When it comes to applying Bernoulli's equation, whether you use gauge pressure or absolute pressure does indeed matter. Bernoulli's equation describes the conservation of energy along a streamline in a fluid flow. It states that the total mechanical energy per unit mass in a fluid remains constant along a streamline, neglecting friction and other dissipative forces.

Now, if you're using gauge pressure, you're measuring pressure relative to atmospheric pressure. In contrast, absolute pressure includes atmospheric pressure as a reference point. So, in essence, using gauge pressure implies that you're already factoring out atmospheric pressure from your calculations.

When applying Bernoulli's equation, the choice between gauge and absolute pressure depends on the context of the problem. If the problem involves pressures relative to atmospheric pressure, gauge pressure is appropriate. However, if you need to consider the absolute pressure in the system, you should use absolute pressure in your calculations.

For instance, in scenarios like airflow over an airfoil or water flow through a pipe, gauge pressure might suffice since atmospheric pressure acts equally on all points. But in situations where you're dealing with pressures inside a closed vessel or a vacuum system, absolute pressure becomes crucial.

In conclusion, while both gauge and absolute pressures have their applications, understanding when to use each is vital for accurate and meaningful application of Bernoulli's equation in fluid dynamics.