Under most scenarios, the fluid flowing over an external body sticks to the surface of the body. In fluid dynamics, this is called the no-slip condition. However, under specific conditions, the flow over the body separates from the surface. This phenomenon is commonly referred to as flow separation and occurs in both external and internal flows, creating a recirculating region near the wall. From an engineering standpoint, flow separation increases the drag force (in external flows) and the pressure drop (in internal flows). In this lesson, we will explore the physics of flow separation and learn how to predict the separation point.
Here are the accompanying handout slides for this lesson.