What is the purpose of flexible units in the ducting system?

The purpose of flexible units in the ducting system is to allow for movement of the ducts due to temperature and pressure changes. As air is heated or cooled, the ducting may expand or contract; similarly, changes in pressure can create shifts in alignment. Flexible ducting can accommodate these changes without causing damage or creating leaks in the system, ensuring that airflow remains efficient and effective throughout various operating conditions. This adaptability is crucial for maintaining proper airflow and system integrity, which ultimately supports the overall performance of the aircraft's ventilation or exhaust system.