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GATE 2020 ME (ME2) – Question 58

Fluid Mechanics · Bernoulli's equation and fluid acceleration · 2 marks · Numerical answer

The nozzle carries steady incompressible inviscid air of density 1.23 kg/m³. Inlet area is 0.2 m²; outlet area 0.02 m², outlet speed 50 m/s and outlet pressure atmospheric. Find inlet minus atmospheric pressure (kPa), to two decimals.

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Correct answer: 1.5 to 1.55

Explanation

Continuity givesV1=(A2/A1)V2=5 m/s. Bernoulli for a horizontal inviscid flow givesp1−patm=ρ(V2²−V1²)/2=1.23(2500−25)/2=1522.125 Pa=**1.52 kPa**.