I know the theorem says that fluid pressure goes down as fluid velocity increases, but what exactly does fluid pressure mean in this context? or do I just have the wrong idea for Bernoulli’s theorem? I am very smol brain
In: Physics
I learned it as ‘how hard the fluid is pushing on the pipe’.
My teacher explained it like ‘it’s easier to push on a wall when you’re standing still than while you’re running’. Probably not the most scientific explanation, but that’s the easiest explanation I know.
Bernoulli’s principle is a derivation of the conservation of energy – a fluid contains a given amount of energy, in this case we are looking at the trade-off between potential and kinetic energy.
The kinetic component is related to how fast the fluid is moving
The potential component is a combination of gravitational potential and pressure energy. In Bernoulli’s principle, he limits the application to horizontal flow, so the gravitational component is constant, and can be discarded.
Pressure potential energy is a measure of how much force each fluid molecule is applying to its neighbours. The more pressure applied to a fluid, the closer the molecules get together, and the force they apply on each other increases (sort of like compressing a spring).
As energy can’t be created out of nothing, as the flow velocity (and hence kinetic energy) increases, it must be accompanied by a proportional decrease in pressure (i.e. potential energy) and vice-versa – otherwise we are creating energy out of nothing
A very easy way to visualise bernoullis theorem is to watch water flow from a larger to a smaller pipe..
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