Boundary Layer, In Fluid Dynamics, Thin Layer of a Fluid or Fluid In Contact With an Aero Plane Wing Surface, or the Interior of a Pipe, For Example. Sliding Forces Are Added to the Fluid In the Limit Sheet. There Are a Number of Speeds from Max and Zero Around the Boundary Layer, Given the Fluid Is In Contact With the Earth. Boundary Layers at the Front of the Wing and Thicker to the Trailing Edge Are Finer. the Movement of These Boundaries In the Leading or Upstream Segment Is Usually Laminar, and Chaotic In the Trailing or Downstream Section.