JNTU B.Tech II AERODYNAMICS - I Previous Question Paper (October - 2020 - R18)

The pressure coefficient C_p is defined as the ratio of the pressure difference to the dynamic pressure of the free stream. Using Bernoulli's equation for incompressible flow, the formula is:

Given the free stream velocity V_∞ = 45 m/s and the local velocity V = 70 m/s, the calculation is as follows:

The pressure coefficient at the given point on the airfoil is approximately -1.42.

Viscosity is the property of a fluid that measures its resistance to gradual deformation by shear stress or tensile stress. It is essentially the internal friction between fluid layers moving at different velocities.

The boundary layer is the thin region of fluid flow adjacent to a solid surface where the effects of viscosity are significant. Outside this layer, the flow can be treated as inviscid.

Key concepts of the boundary layer include:

• At the surface, the fluid velocity is zero relative to the body due to the no-slip condition.
• As the distance from the surface increases, the velocity increases until it reaches the free stream velocity.
• The boundary layer grows in thickness along the surface in the direction of flow.
• Flow within the boundary layer can be laminar (smooth, ordered layers) or turbulent (chaotic, mixing layers) depending on the Reynolds number.

A sketch would show a solid surface with a velocity profile starting at zero at the wall and asymptotically approaching the free stream velocity, with the boundary layer thickness δ defined as the distance from the wall where the velocity reaches 99% of the free stream value.