Question

The potential lines for a doublet flow are

• A. Straight radial lines
• B. Concentric circles
• C. Circles passing through the origin
• D. Parallel straight lines

Hint:

For a doublet flow, \[ \boxed{ \begin{aligned} \text{Equipotential lines} &\rightarrow \text{Circles through the origin} \text{Streamlines} &\rightarrow \text{Circles about the axis} \end{aligned} } \]

Answer 1

The Correct Option is C

Step 1: Recall the characteristics of doublet flow. A doublet is formed by bringing a source and a sink of equal strength infinitely close together. Its velocity potential and stream function generate two orthogonal families of curves.

Step 2: Identify the potential lines. For a doublet, \[ \boxed{ \text{Equipotential lines are circles passing through the origin.} } \] The streamlines are circles centered on the axis of the doublet. Therefore, \[ \boxed{\text{Circles passing through the origin}} \] is the correct answer. Thus, \[ \boxed{(C)} \] is the correct answer.