u=x2y,v=−2yz2,w=−zy2+32z3Then
∂x∂u=2xy,∂y∂v=−2z2,∂z∂w=−y2+2z2 For a three-dimensional steady incompressible flow the continuity equation can be written in differential form as
∂x∂u+∂y∂v+∂z∂w=0 Substitute
∂x∂u+∂y∂v+∂z∂w=2xy−2z2−y2+2z2
=2xy−y2=0Hence the continuity equation for an incompressible flow is not satisfied. Therefore, it is not a possible incompressible flow.
If a fluid flow is given by : V=xy2i−2y2zj−(zy2−32z2)k, then
u=xy2,v=−2yz2,w=−zy2+32z3
∂x∂u=y2,∂y∂v=−2z2,∂z∂w=−y2+2z2 For a three-dimensional steady incompressible flow the continuity equation can be written in differential form as
∂x∂u+∂y∂v+∂z∂w=0 Substitute
y2−2z2−y2+2z2=0 Hence the continuity equation for an incompressible flow is satisfied. Therefore, it is a possible incompressible flow.
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