Question

For stream function $\psi =3x^2-y^3$, the magnitude of velocity at the point (2,1) is

• A. 12.37
• B. 12
• C. 13
• D. 13.5

Answer 1

The correct option is A 12.37

(a)

$u=\frac{\partial \psi }{\partial y}=3y^2=3units$

$v=\frac{\partial \psi }{\partial x}=6x=12units$

$V=\sqrt{u^2+v^2}=12.37units$