INTRODUCTION

Airfoil, shaped surface, such as an airplane wing, tail, or propeller blade, that produces lift and drag when moved through the air. An airfoil produces a lifting force that acts at right angles to the airstream and a dragging force that acts in the same direction as the airstream. 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.

In fluid dynamics, drag (sometimes called air resistance, a type of friction, or fluid resistance, another type of friction or fluid friction) is a force acting opposite to the relative motion of any object moving with respect to a surrounding fluid. The lift force, lifting force or simply lift is the sum of all the forces on a body that force it to move perpendicular to the direction of flow. The most common type of lift is that of a wing of an aircraft.

the drag coefficient is defined as

where:
F_d is the drag force, which is by definition the force component in the direction of the flow velocity,
rho is the mass density of the fluid,
u is the flow speed of the object relative to the fluid,
A is the reference area.

the lift coefficient is defined as

where  L is the lift force, S is the relevant surface area and q is the fluid dynamic pressure, in turn linked to the fluid density rho and to the flow speed u. 

FOUR FORCES AFFECT THINGS THAT FLY:

1. Weight is the force of gravity. It acts in a downward direction—toward the center of the Earth.
2. Lift is the force that acts at a right angle to the direction of motion through the air. Lift is created by differences in air pressure.
3. Thrust is the force that propels a flying machine in the direction of motion. Engines produce thrust.
4. Drag is the force that acts opposite to the direction of motion. Drag is caused by friction and differences in air pressure.

Air foil taken for analysis: HAWKER TEMPEST 96.77% SEMISPAN AIRFOIL (tempest3-il): HAWKER TEMPEST 96.77% SEMISPAN AIRFOIL - Hawker Tempest 96.77% semispan airfoil  

Fluid: Air

velocity: 600 m/s(along X-axis)

NOTE: Gravity is considered in Y-axis(downwards which means negative)

PROCEDURE FOR DOING FLOW OVER AN AIRFOIL USING SOLID WORKS

Step 1: Creating the cad model for the foil(Insert the curve - check the curve is fully closed - boss extrude from mid plane. And save the part.

Step 2: Click flow simulation 

1. Project name
2. Unit system
3. Analysis type- external, Time deoendent, gravity.
4. Fluid- air
5. condition- velocity along x- axis

Step 3: Setting domain- from angle attack point to before 5 times chord length and after 15 times the chord length

Step 4: Assigning goals.

Step 5: Creating localised mesh on the surface.

Step 6: Run the simulation.

Step 7: Now click on results and insert the goal plot(where we can see the result values). 

Step 8: We can also see the velocity and pressure with cut plot option.

Step 9: we an export to excel and we can plot the drag and lift plots obtained during simulation.

FLOW ANALYSIS CONDITION USED:

RESULTS

'0'angle of attack:

'2'angle of attack:

'4'angle of attack:

'6'angle of attack:

'8'angle of attack:

'10'angle of attack:

Pressure and Velocity plots:

cases	Angle of attack(deg)	velocity	pressure
1	0
2	2
3	4
4	6
5	8
6	10

CONCLUSION

We can get the average drag-and-lift force from the simulation. Using that we can compute each focussed coefficient. The plot of force Vs angle of attack represents as the angle of attack increases the increase of the lift force (directly suggestive) but the drag force increases slightly after 5deg.

The airfoil analysis is performed on a design perspective to find the critical angle of attack. And we can assume that the airfoil doesn't surpass the angle of attack.But we can not conclude the critical angle from the plot since the lift and drag force do not meet at a particular point (the design is concluded at two points between the combination of forces). The conclusion is as high as 10 deg the critical angle of attack is not obtained so that the foil can use the angle of attack(4 to 10 deg). If we go up the angle of attack we can determine the critical angle of attack.