Question

The stream function for a two-dimensional flow is given by $\psi =2xy$. The resultant velocity at a point P(2,3) is

• A. 8.45 units/s
• B. 7.21 units/s
• C. 6.44 units/s
• D. 5.18 units/s

Answer 1

The correct option is B 7.21 units/s

$u=-\frac{\partial \psi }{\partial y}=-2x=-4units$

$v=\frac{\partial \psi }{\partial x}=2y=6units$

$V=\sqrt{u^2+v^2}=\sqrt{16+36}$

= 7.21 units