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To understand how airfoils work, a basic understand of aerodynamics is needed. One of the most important laws of aerodynamics is Bernoulli's principle. Bernoulli's Principle states that as the speed of a moving fluid increases, the pressure within the fluid decreases. This principle also applies to matter in the gas state, such as air. The principle can be used to explain how airfoils create lift. Lift occurs when there is enough pressure difference between the top and bottom sides of the airfoil.

The top side of the airfoil is more curved than the bottom side. It will take the air the same amount of time to travel over both side, but since the top side is curved, the air has a greater distance to travel. Therefore the velocity of airflow over the top side is greater than the bottom surface. This causes the pressure difference between the two sides, and is essentially the reason for lift. This effect is shown in diagram A.

When there is a sufficient difference in pressure between the two sides, another effect happens. Since there’s no barrier between the two sides, the air begins to neutralize by mixing at the tips of the airfoil. The effect is called wing tip vertices. The air circulates from higher pressure to lower pressure and neutralize. This reduces the amount of lift an airfoil produces, and can sometimes eliminate the pressure difference. On airplanes, the wings are designed to eliminate this effect, making them more efficient. The effect is shown in Diagram A.

This effect can be prevented with the addition of endplates at the tips of the airfoil; which act as a barrier between the two sides. However, the effect is still visible on airplanes. White stripes of air are left behind the wings as the airplane flies. The spiral effect is shown in diagram C.

The airfoil properties examined above were important for predicting the hypothesis. By placing a hole in the airfoil, the wing tip vertices effect will remain, only it will be redirected through the hole as shown in diagram A1. The pressure difference between the top and bottom side of the airfoil will start neutralizing in the hole rather than the tips. This will create excessive airflow through the hole, potentially at a faster velocity then surrounding airflow. With the addition of endplates at the tips of the airfoil, the neutralization between the pressures will happen only through the hole. When in motion, air will be sucked from the bottom and enter out of the top side of the airfoil as illustrated in diagram C1.

My prediction is that the velocity of airflow through the hole will be greater than the velocity of airflow relative to the airfoil.

Another important factor that has to be considered is how the pressure is spread over the airfoil. This can be determined by examining the pressure gradient of the airfoil. It is used to determine various properties of a specific airfoil such as where the maximum and minimum pressure is located. The diagram looks different for every profile, but the overall pattern is similar. The maximum pressure is at the maximum thickness of the profile, and the minimum pressure is usually at the rear of the profile. An example of a pressure gradient is shown in diagram D.