The stream function in a two dimensional flow field is

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The stream function in a two dimensional flow field is given by ψ = x² – y² The magnitude of the velocity at point (1, 1) is

1. 2
2. 2√2
3. 4
4. 8

Correct Option: B

Stream function, ψ = x² – y²

u =	-∂ψ	=	-∂	(x² - y²) = 2y
	∂y		∂y

or V =	-∂ψ	=	∂	(x² - y²) = 2x
	∂x		∂x

V = uî + vĵ at (1, 1) = 2î + 2ĵ
V = √(2)² + (2)² = 2√2