Non uniform flow occurs when A. the direction and magnitude of the velocity at all points are identical B. the velocity of successive fluid par-ticles, at any point, is the same at suc-cessive periods of time C. the fluid particles move in plane or parallel planes and the streamline pat-terns are identical in each plane D. velocity, depth, pressure, etc. change from point to point in the fluid flow.

The correct answer is D.

Non-uniform flow occurs when velocity, depth, pressure, etc. change from point to point in the fluid flow. This means that the direction and magnitude of the velocity at different points in the fluid are not the same.

Option A is incorrect because it describes uniform flow. In uniform flow, the direction and magnitude of the velocity at all points are identical.

Option B is incorrect because it describes steady flow. In steady flow, the velocity of successive fluid particles, at any point, is the same at successive periods of time.

Option C is incorrect because it describes laminar flow. In laminar flow, the fluid particles move in plane or parallel planes and the streamline patterns are identical in each plane.

I hope this helps! Let me know if you have any other questions.