Orifice flow occurs through regions of severe constriction. Which option correctly identifies this condition?

Orifice flow occurs through regions of severe constriction. Which option correctly identifies this condition?

• A. Through parallel-sided tubes
• B. Through constricted regions
• C. In a vacuum
• D. At extremely high velocity

Answer: (B)

Orifice flow is the movement of fluid as it passes through a narrow opening that constricts the path. The key idea is continuity: the same volume flow must pass, so when the cross-sectional area decreases at the constriction, the fluid must speed up. This acceleration through the restricted region (and the associated drop in static pressure) is what characterizes orifice flow. That’s why the correct identification is flow through constricted regions—the geometry of a narrow opening is what defines this type of flow. Flow through a uniform tube, flow in a vacuum, or merely achieving very high speeds without a constriction don’t capture that essential constricted passage.

Orifice flow is the movement of fluid as it passes through a narrow opening that constricts the path. The key idea is continuity: the same volume flow must pass, so when the cross-sectional area decreases at the constriction, the fluid must speed up. This acceleration through the restricted region (and the associated drop in static pressure) is what characterizes orifice flow. That’s why the correct identification is flow through constricted regions—the geometry of a narrow opening is what defines this type of flow. Flow through a uniform tube, flow in a vacuum, or merely achieving very high speeds without a constriction don’t capture that essential constricted passage.