Re-Entrant Orifices

07/03/26

“What’s so special about orifices that extend into their container?”

Orifices are openings in containers. In water systems, they’re pipes that allow for gravity-based release. Orifices whose pipe extends into the tank itself are called Re-Entrant Orifices. For these orifices, the water will flow to the tube from all directions, leading to a sharp turn inwards and a significant stream contraction, leading to a jetting on the other end. These features lead to a smaller discharge coefficient, thereby limiting flow. Re-entrant orifices are useful for applications where flow downstream of the container must be controlled.

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