The theoretically correct model mentioned in the idealization only does not correspond to the physical processes observed in reality. According to the Potential Theory, the characteristic curve of pressure for the flow model illustrates that the equilibrium of forces takes place at high magnitudes of forces in a direction transverse to the flow direction.
In reality this streamline characteristic curve up to the largest cross-section corresponds very well to this model. In this case, the flowing medium above and below the ram point is initially accelerated. According to the Law of Conservation of Energy (Bernoulli's Equation) the local pressure decreases with an increasing flow velocity. For any point i along the streamline it follows:
