🔍 Key Concepts

• Flow through a convergent nozzle vs a divergent diffuser • Relationship between velocity and pressure in a duct (Bernoulli principle) • What an exhaust diffuser is designed to do in gas turbines and diesel engines

💭 Think About

• When gas flows from a smaller cross‑section to a larger one at subsonic speeds, what typically happens to its velocity and static pressure? • In an exhaust system, why might engineers want to slow the gas down after it leaves the turbine or engine? What benefit does that give to the system? • Which of the answer choices matches the usual function of a diffuser section rather than a nozzle section?

✅ Before You Answer

• Identify which answer choice describes a change that normally happens in a diffuser (divergent duct) for subsonic flow. • Make sure you are not mixing up the behavior of nozzles (convergent) with diffusers (divergent). • Confirm that your chosen option aligns with improving pressure recovery and reducing flow losses in the exhaust system.