Final answer:
The two main patterns of flow are laminar and turbulent, with laminar flow featuring smooth and continuous streamlines and turbulent flow having irregular and mixing streamlines caused by obstructions and high speeds.
Step-by-step explanation:
The two main patterns of flow are laminar and turbulent flow. Laminar flow is characterized by smooth, parallel layers of fluid that flow without mixing. The streamlines in laminar flow are smooth and continuous. In contrast, turbulent flow features irregular movement of fluid layers, leading to mixing, swirling, and eddies. Streamlines in turbulent flow are broken and mixed due to the chaotic movement of the fluid.
Turbulence can be caused by obstructions, sharp corners, and high velocities that impose perpendicular forces to the overall direction of flow, creating a resistance greater than what is present in laminar flow. Laminar flow is typically found at lower velocities, in smooth tubes, or around streamlined objects, while turbulent flow is more likely at high speeds or in the presence of certain geometric constraints.