Bernoulli Pressure Change
Bernoulli Pressure Change
Along a streamline, where the fluid speeds up its pressure drops — Bernoulli’s principle, the basis of lift, venturis and carburettors.
At constant height p_2 = p_1 + ½·ρ·(v_1² − v_2²). where p_1, v_1 are the upstream pressure and velocity and v_2 the downstream velocity.
Inputs
p_1 := 200 kPa=200000 Pa
rho := 1000 kg/m^3=1000 kg/m^3
v_1 := 2 m/s=2 m/s
v_2 := 5 m/s=5 m/s
Apply Bernoulli at constant elevation.
p_2 := p_1 + 0.5·rho·(v_1^2 - v_2^2)=189500 Pa
Results
The faster section has lower pressure. Measuring this pressure drop is how a venturi meter infers flow rate.
Assumptions & limitations
- Incompressible, inviscid, steady flow.
- Same elevation.
- Along one streamline.