Govt Exams
In a convergent-divergent nozzle, throat area is smallest and exit area is larger for supersonic flow.
Friction factor for turbulent flow depends on Re and roughness (ε/d) as shown in Moody diagram.
ΔP = ρgh = ρ_mercury × 9.81 × 0.05 ≈ 50 × ρ_mercury × g Pa (approximately)
Cd < 1 accounts for vena contracta and frictional losses in actual orifice flow compared to ideal flow.
Force F = ρAv² = 1000 × 0.01 × 10² = 1000 N (using ρ = 1000 kg/m³ for water)
From Bernoulli's equation applied between static and stagnation points: v = √(2ΔP/ρ)
Boundary layer develops due to viscous effects that cause velocity gradient near solid surfaces, creating shear stress.
Hagen-Poiseuille equation is valid for incompressible, fully developed laminar flow in circular pipes without entrance effects.
Kinematic viscosity ν = μ/ρ = 0.8/800 = 1.0 × 10⁻³ m²/s
Major losses or friction losses occur due to wall shear stress and account for the majority of energy dissipation in long straight pipe sections. This is captured by the Darcy friction factor.