Skip to content
Observe and discuss 2.9 · Q1

Q.Observe the shape of blades of a fan and discuss the nature of the air flow when fan is switched on.

Maharashtra MsbshseTextbookSubjectiveImportance★★★★★
38% · 39/104 Questions
🔒 Locked · start free trial →

You're viewing a preview — the full solution, concept, methods & PYQ mapping are locked.

Start your 14-day free trial to unlock the full solution →

Tilted aerofoil blades pump an axial, partly turbulent jet.

Each fan blade is a cambered, TWISTED plate — an aerofoil whose pitch angle varies along its length so that every radius pushes its ring of air equally. Spinning, a blade's leading face compresses the air ahead (higher pressure) while its trailing face runs with faster, lower-pressure flow — the Bernoulli pressure difference across each blade element is what propels the air axially through the fan disc. The emerging jet is swirling and, at the speeds of a domestic fan, largely turbulent at its boundary where it shears against still air (which is also why fans are heard as a rushing noise). This blade-element picture is the household cousin of propellers and turbines. …

Unlock everything free for 14 days

  • Full step-by-step solutions
  • Concept-first explanations
  • Methods, shortcuts & mistakes
  • PYQ mapping + timed mock tests

Full access for 14 days. No credit card required.