Laminar boundary layer flow has the aerodynamic advantage of:

• A. Low skin friction drag
• B. High skin friction drag
• C. Increased turbulence
• D. Increased heat transfer

Answer: (A)

Laminar boundary layer flow yields lower skin friction drag because the fluid moves in smooth, parallel layers with minimal momentum exchange near the surface. The wall shear stress is smaller than in a turbulent boundary layer, where chaotic eddies and strong mixing increase momentum transfer to the wall. So, when the boundary layer stays attached, laminar flow experiences less friction drag than turbulent flow. Turbulence, while more resistant to separation in some cases, carries higher skin friction due to its increased shear and mixing, and it also enhances heat transfer. Keep in mind, laminar flow is more prone to separation under adverse pressure gradients, which can offset the drag benefit if separation occurs.