Jawaharlal Nehru Technological University Hyderabad B.Tech II AERODYNAMICS - I Previous Question Paper (August/September - 2022 - R18)

Fluid properties are physical characteristics that define the state and behavior of a fluid. Three primary properties are:

1. Density (ρ): Defined as the mass per unit volume of a fluid. It represents the degree of compactness of the fluid particles. The SI unit is kg/m³.
2. Viscosity (μ): A measure of a fluid's resistance to gradual deformation by shear stress or tensile stress. It is essentially the internal friction of the fluid. The SI unit is N·s/m² or Pa·s.
3. Specific Weight (γ): Defined as the weight per unit volume of a fluid, calculated as the product of density and acceleration due to gravity (γ = ρg). The SI unit is N/m³.

The pressure coefficient (C_p) is a dimensionless number used in aerodynamics and fluid mechanics to describe the relative pressures throughout a flow field. It is derived from Bernoulli's equation for incompressible, steady, irrotational flow:

Rearranging this to isolate the pressure difference gives:

Dividing both sides by the dynamic pressure (q_∞ = 1/2ρV_∞²) yields the definition of the pressure coefficient:

The importance of C_p includes:

• It allows for the comparison of pressure distributions over geometrically similar bodies regardless of the flow velocity or fluid density.
• It is essential for calculating the lift and drag forces on an airfoil by integrating the pressure distribution over the surface.
• It helps identify regions of high pressure (stagnation points where C_p = 1) and low pressure (suction peaks), which are critical for analyzing flow separation and aerodynamic performance.