Final answer:
The type of airflow normally present within the transonic regime is transitional, oscillating between laminar and turbulent flow depending on factors such as the Reynolds number.
Step-by-step explanation:
The type of airflow normally present within the transonic regime is transitional, which oscillates between laminar and turbulent flow. In the transonic regime, the flow can chaotically transition between laminar flow (where layers of fluid move in parallel, regular paths) and turbulent flow (where regions of fluid move in irregular, colliding paths), depending on various factors such as the Reynolds number.
For Reynolds numbers (NR) below about 2000, flow is laminar, while for NR above about 3000, flow is turbulent. In the transition region, NR values between 2000 and 3000, the flow can exhibit characteristics of both laminar and turbulent flow.
For example, in blood vessels, the flow is laminar in the large part of the vessel and turbulent in the narrowed part with plaque, where the velocity is high. The transition region between these two flow types can lead to chaotic oscillations between laminar and turbulent flow.