Tank Drainage Velocity: Does Area Matter?

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Discussion Overview

The discussion revolves around the relationship between the area of a drainage hole and the velocity of fluid draining from a tank. Participants explore the implications of Bernoulli's equation and the mass continuity principle in this context, focusing on whether the area of the drainage hole affects fluid velocity calculations.

Discussion Character

  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant questions whether the area of the drainage hole impacts fluid velocity, suggesting that it seems neglected in velocity calculations based on Bernoulli's equation.
  • Another participant asserts that the drainage opening does appear in the velocity calculations, prompting a request for clarification on the specific calculation scheme being referenced.
  • A participant points out that Bernoulli's equation simplifies to V =(2gh)^(1/2), which does not include the diameter of the hole, indicating a perceived omission of area in the velocity equation.
  • It is noted that velocity is distinct from volumetric flow rate, which depends on both velocity and area, and that Bernoulli's equation relates velocity to pressure rather than directly incorporating area.

Areas of Agreement / Disagreement

Participants express differing views on the role of the drainage hole's area in fluid velocity calculations, indicating that multiple competing perspectives remain unresolved.

Contextual Notes

There are limitations regarding the assumptions made in applying Bernoulli's equation and the mass continuity principle, as well as the specific conditions under which these equations are valid.

UMath1
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Using Bernoulli's equation to calculate the velocity of fluid draining from a tank seems to give no weightage to the area of the drainage hole. But based on the mass continuity principle, the area of the hole should have an impact. Does the area of a drainage hole have an impact on the fluid velocity or not? And why does it appear to be neglected in velocity calculations?
 
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The drainage opening does appear in the velocity, e.g. here. What calculation scheme are you referring to ?
 
Yes that's a first. But still it does not appear in the equations used to calculate the velocity which is Bernoulli's equation. Bernoulli's equation simplifies to V =(2gh)^(1/2). This does not include the diameter of the hole.
 
Velocity isn't volumetric flow rate. The volumetric flow rate depends on the velocity and area. Bernoulli's equation relates velocity to pressure.

It is similar to the difference between pressure and force. You don't necessarily need to relate them.
 

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