Simulation of NACA Airfoil

Introduction:

An airfoil is the cross-sectional shape of a wing, blade of a propeller, rotor, or turbine, or sail.

An airfoil-shaped body moving through a fluid produces an aerodynamic force. The component of this force perpendicular to the direction of motion is called lift. The component parallel to the direction of motion is called drag. Sunbsonic flight airfoils have a characteristic shape with a rounded leading edge, followed by a sharp trailing edge, often with a symmetric curvature of upper and lower surfaces. Foils of similar function designed with water as the working fluid are called hydrofoils.

The lift on an airfoil is primarily the result of its angle of attack. When oriented at a suitable angle, the airfoil deflects the oncoming air (for fixed-wing aircraft, a downward force), resulting in a force on the airfoil in the direction opposite to the deflection. This force is known as aerodynamic force and can be resolved into two components: lift and drag.

The geometry of the airfoil is described with a variety of terms :

• The leading edge is the point at the front of the airfoil that has maximum curvature (minimum radius).
• The trailing edge is defined similarly as the point of maximum curvature at the rear of the airfoil.
• The chord line is the straight line connecting leading and trailing edges.

In this study i have used a NACA 2415 series (to be read as 2 – 4 – 15) describes an airfoil with a camber of 0.02 chord located at 0.40 chord, with 0.15 chord of maximum thickness.

• The model is generated by extruding to 400mm.
• In our study we perform the analysis by varying the angle of attack.From 0-10 with increments of 2.(i.e 0,2,4,6,8,10).
• Intial setup is done. S.I unit system is selected for the unit system.
• Analysis type is external, as the air flows over the surface of the airfoil.
• Time dependent feauture is enabled. Total analysis time is set to 5secs, and the time stepping is set to 1sec.
• In the Fluid Wizard Air is selected as the fluid, with its default properties from the solidworks library.
• In the initial ambient condition wizard the velocity component along the x direction is set to 600m/s. and the analysis run.
• Then for the varying angle of attack the parameteric study is conducted.

The drag and lift forces are calculated:

The Surface force along the X direction is Drag force.

The Surface force along the Y direction is Lift force.

• The simulation is run at a subsequent iterations so that the solution converges to the optimum value.
• Following pictures will give us the number of iiterations and also the iteration at which the solution has converged.

Run at 0deg Angle of attack.

Run at 2deg Angle of attack:

Run at 4deg Angle of attack:

Run at 6deg Angle of attack:

Run at 8deg Angle of attack:

Run at 10deg Angle of attack:

The Velocity contours at different angle of attack are obtained by the simulatiion.

At 0 Deg Angle of attack.

At 2 deg angle of attack:

At 4deg angle of attack:

At 6deg angle of attack:

At 8deg angle of attack:

At 10deg angle of attack:

Conclusion:

• With increased angle of attack, lift increases in a roughly linear relation.
• With Further observation the the Stalling conditions will be achieved.
• From internet sources it is said that stalling condition will be achieved in range odf 15°-20° angle of attack.