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GATE 2023 AE – Question 14

Aerodynamics · Airfoils and wings: coefficients, Kutta-Joukowski theorem, thin airfoil theory, finite wing theory, critical and drag divergence Mach numbers · 1 mark · Multiple choice

A two-dimensional potential flow solution for flow past an airfoil has a streamline pattern as shown in the figure. Which of the following conditions is additionally required to satisfy the Kutta condition?

source diagram and its labels are reproduced in the attached image.
  1. Addition of a source $Q>0$
  2. Addition of a source $Q<0$
  3. Addition of counter-clockwise circulation $\Gamma>0$
  4. Addition of clockwise circulation $\Gamma<0$

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Correct answer: (D) Addition of clockwise circulation $\Gamma<0$

Explanation

Clockwise circulation accelerates the upper-surface flow and shifts the rear stagnation point to the sharp trailing edge, enforcing smooth departure.