TYPES OF DRAGS

4 min readNov 12, 2017

Have you ever ridden a two-wheeler and felt the wind rush past your face? It’s exhilarating, and you feel dynamic. Ever felt that way?

We can consider the car as another example. In an open-top car, it is interesting when we normally don’t feel the air. Although the atmosphere is spread with discrete gas, life is impossible without it. Comprehending this nature of air, we slice through the speed and other aspects of drag.

So, what is a drag? And what are its types that oppose the aircraft motion through the air and gives us this feel? Let’s take a closer look!

What is a Drag?

The aerodynamic force exerted on an airplane or other aerodynamic bodies that tend to reduce its forward motion.

When the F1 car speeds through the air, the flow remains constant along the streamlines, without any turbulence. Drag is one of the force in aerodynamic, that a moving body can feel when the flow of air around its system starts to become turbulent.

In this context, you can find out why a drag takes place during the dynamic motion of an object and the types of drag.

I. PARASITE DRAG:

This drag is produced due to the air molecules acting in the shape of the aircraft, construction type, and material. It is also produced due to the motion of the object (aircraft) through the fluid (atmospheric air).

The parasite drag can be further classified as:

1. Skin friction drag.

2. Form drag.

3. Interference drag.

 Skin friction drag:

The best way to understand a skin friction drag is considering a swimmer’s cap. Ever wondered why they wear swim caps and tuck their hair in? What happens if the swimmer has not put on his cap? The swimmer must do more strokes in the water to overcome skin friction. Similarly, an aircraft experiences this resistance when the surfaces are not smooth. Thus, a skin friction drag is an aerodynamic resistance experienced by the aircraft due to contact of air with respect to the surface of the aircraft. Smooth skin reduces skin friction drag and thereby improving the performance and fuel efficiency.

 Form drag:

The drag created due to the shape and area of the cross-section of the solid body moving through the fluid. This is created due to the viscous flow to be faced with an adverse pressure gradient. Imagine that you are holding a cardboard sheet upright in front of a table fan. Move the sheet towards the fan with an ease. This is called a form drag. The streamlined shape of body would reduce the form drag. An object with larger cross- section and blunt shape will have larger form drag.

 Interference drag:

This drag is produced due to the interference of two or more airflow having different speed, also by the interference of different aircraft parts. Such as due to a mixture of airflow around the fuselage.

II. PROFILE DRAG:

Is defined as the sum of form drag and skin friction drag. The portion of the wing drag that is due to turbulence and friction in the fluid, that would be absent if it were a non-viscous flow.

III. LIFT-INDUCED DRAG:

Considering the change in vector direction of lift of the aircraft. The production of vortices is due to high- pressure airflow which gets pulled towards low-pressure airflow. In such a way lift-induced drag is produced with a lift.

 Dynamic induced drag:

Going back to the example of the moving car discussed earlier in the introduction, depending on the angle of attack there will be a force (induced drag) and a force upward (lift). If the angle of attack is small compared to the lift and drag. Any increase in the angle of attack up to a certain point will result in increasing the drag as well as the lift. If you were to hold your hand vertical to the relative wind, the only force would be backward is the dynamic drag.

 Pressure Drag:

Is caused due to the particles of air being more compressed on the front and facing surfaces and more spaced out on the back surfaces. This is caused when the layers of ar in the atmosphere separate away from the surface and begin to swirl (turbulent flow).

IV. WAVE DRAG:

Takes place due to shock waveforms over or in front of the air pressure. Consider a supersonic flight around some surface of the aircraft in a transonic flight. The formation of shock waves causes a wave drag.

V. FRICTION DRAG:

This force is due to the resistance that happens due to two things rub together like an air against airplane. Friction is the reason behind the cause of drag.

VI. VISCOUS DRAG:

If a fluid in laminar flow flows around an object, it exerts a viscous drag on the obstacle.

While flying in an airplane, you feel the air push past you. A person observes you through fairly stationary air.

VII. RAM DRAG:

The loss of turbojet engine caused by increase in velocity of air entering the engine. Thus ram drag can be defined as the difference between gross thrust and the net thrust. Low pressure type of suction that might help pull the jet engine forward to a slight extent.

VIII. TOTAL DRAG:

It can be defined as the sum of parasite drag and the induced drag.

TYPES OF DRAGS

Written by Team Arcis