Physics 4 — Thermo & Fluids

Fluids in motion — Bernoulli

continues from lesson 4 — values defined earlier in the course stay live here

ELI5: energy bookkeeping for flowing fluid: where a pipe narrows, the fluid speeds up — and to pay for that speed, its pressure drops. Fast fluid is low-pressure fluid. (Continuity sets the speed; Bernoulli prices it in pressure.)

v_{1} := 2 m/s

= 2 m / s speed in the wide section

A_{ratio} = 4

wide-to-narrow area ratio

v_{2} = v_{1} \cdot A_{ratio}

= 8 m / s same flow through ¼ the area

dP = \frac{1}{2} \cdot \rho_{w} \cdot \left(v_{2}^{2} - v_{1}^{2}\right)

= 30000 Pa pressure DROP in the narrow section (Pa)

Real-world hook: Bernoulli is the lift on an aeroplane wing, the curve on a spinning ball, why a shower curtain sucks inward, and how a carburettor or perfume atomiser pulls fluid up. Where next: Physics 5 — where classical physics breaks.