Limitation of Bernoulli's Equation:
1. The velocity of liquid particles in the center of a pipe is maximum and gradually decreases towards the wall of the pipe due to friction. so only the mean velocity of the liquid should be taken into account because the velocity of liquid particles is not uniform.
2. There is always some external force acting on the liquid, which affects the flow of liquid. so we have to neglect all such external forces.
3. In turbulent flow, some kinetic energy is converted into heat energy and in viscous flow, some energy is lost due to shear force. so all such losses should be neglected.
4. If the liquid is flowing through a curved path, then energy due to centrifugal forces should also be taken into account.