When a particle enters the boundary layer

When a particle enters the boundary layer, it experiences a change in its behavior due to the interaction with the fluid flow. The boundary layer is a thin layer of fluid that forms near a solid surface, where the velocity of the fluid gradually decreases from the free stream velocity to zero at the surface. As the particle enters the boundary layer, it will be influenced by the slower velocity of the fluid in that region. This can lead to various effects depending on the size and characteristics of the particle. For example, small particles may follow the fluid flow closely and be carried along with it, while larger particles may experience more resistance and deviate from the flow path. In addition, the boundary layer can also affect the heat and mass transfer between the particle and the fluid. The presence of the boundary layer can enhance or hinder these transfer processes, depending on the specific conditions. Overall, when a particle enters the boundary layer, its behavior and interaction with the fluid will be influenced by the characteristics of the boundary layer and the particle itself.