What occurs in a convergent duct?

In a convergent duct, fluid dynamics principles dictate that as the flow area decreases, the velocity of the fluid increases. This acceleration of fluid typically leads to a corresponding decrease in both pressure and temperature, which aligns with the application of Bernoulli’s equation and the principles of thermodynamics.

As the fluid is forced through the narrower section of the duct, its speed increases, requiring a drop in pressure to conserve energy. This relationship shows that when velocity rises in a convergent duct, the pressure must decrease. Additionally, due to the conservation of energy and the principles governing compressible flow, an increase in velocity often results in a decrease in temperature as well.

Thus, this option accurately reflects the fundamental behaviors observed in convergent ducts within the context of fluid mechanics and thermodynamic principles.