What effect does fluid velocity have when it passes through a restricted orifice?

When fluid passes through a restricted orifice, its velocity experiences a dramatic increase. This phenomenon is explained by the principle of continuity in fluid dynamics, which states that for an incompressible fluid, the product of the cross-sectional area and the flow velocity must remain constant from one point to another along a streamline.

As the fluid enters a narrower section, the cross-sectional area decreases. To conserve mass flow rate, the fluid must accelerate, resulting in an increase in velocity as it passes through the orifice. This principle is also described by Bernoulli's equation, which indicates that an increase in fluid velocity leads to a decrease in pressure within the fluid.

Options that suggest the velocity remains constant, decreases significantly, or fluctuates randomly do not align with these fundamental concepts. Therefore, the correct understanding of fluid dynamics confirms that the velocity of the fluid indeed dramatically increases as it passes through a restricted orifice.