Explain the working principle of a Pitot tube.

A Pitot tube measures fluid velocity by sensing stagnation and static pressures. The Pitot tube opening faces the flow, bringing fluid to rest (stagnation point) and measuring total pressure (P_total = P_static + ρV²/2). A separate static pressure tap measures ambient pressure. Applying Bernoulli's equation: V = √(2(P_total - P_static)/ρ). For compressible flows, temperature correction is needed. Pitot-static tubes combine both measurements in one probe. Applications: aircraft airspeed indicators, duct velocity measurement, and point velocity surveys in pipes. Accuracy depends on alignment with flow direction (typically ±15° tolerance).