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Monday Mentoring: Five Specialisations of Aerospace Engineering
Aerospace Engineering has five major specialisations: aerodynamics, propulsion, structures, controls and systems.
There are five specialisations in Aerospace Engineering. Every graduate, while having a basic knowledge of all five divisions specialises in one of these fields. An understanding of these divisions will help aspirants to decide, "If Aerospace Engineering is the right choice?". We already talked about these in the first Monday Mentoring post. We will cover these in detail in this article.
Different aerospace departments at various engineering institutes have different terms. In general, the following focus areas constitute Aerospace Engineering.
Dynamics and Control
Design and Systems Engineering
The study of the movement of air around bodies such as aircraft or spacecraft. In turn, there are two classes based on speed, Subsonic and Supersonic. Subsonic deals with bodies moving at speeds less than that of sound, while Supersonic deals with rates higher than the speed of sound. Dealing with Aerodynamics needs a good understanding of fluid mechanics, calculus and programming.
"How a bird or an aeroplane flies?", if you have asked this question, the answer lies within Aerodynamics. Not only aeroplanes, a launch vehicle blasting to space, a racing car on the track or a kite flying, but all these objects are also affected by Aerodynamics.
You may find aerodynamics experts working day-night on a computer screen working on computational fluid dynamics (CFD) models or one may have his/her head inside a wind tunnel, fixing a model for testing. If you are lucky, you may also see the rarer ones, trying to work out Navier Stokes problem or creating a new model.
Structures is the easiest to describe. "Will your mobile phone survive a 10 ft (one floor) fall?". Its build, along with the material, represents this answer. Build depends on the shape and the placement of different joining elements such as nuts and bolts and the manufacturing process determines the material properties. In the end, all the above details are designed to ensure the mobile sustains various forces applied to it.
Similarly, aerospace structures are lightweight structures used for aerospace applications. Aerospace applications have a unique element to them; once deployed, they are tough to be repaired. Therefore, there is a history of various choices which are consistently made in Aerospace Structures. For example, the shape of an aeroplane has changed little in the last several years.
Along with the various details discussed above, Structures experts also design the mechanisms for different purposes such as Solar Panel Deployment.
You must have seen birds flapping their wings. Aeroplane, on the other hand, has fixed wings. Birds don't flap wings to generate upward force (lift) but to produce the forward force (thrust). This is evident if you watch a bird flying at high altitude. With high flowing wind, birds don't require flapping. The study of the generation of this forward force is propulsion.
Propulsion experts work on different techniques to generate propulsive forces. The engines range from air-breathing ones such as Jet Engine, RamJet, ScramJet and non-air-breathing ones like Rocket engines.
Propulsion itself is a very diverse field. For air-breathing engines, both fluid mechanics and thermodynamics are essential. Thermodynamics and Shock Theory is needed for ScramJet and Rocket engines. The propeller blades used for jet engines need aerodynamic studies. The high temperatures encountered have to be accounted for in the structural design. Slowly, the complexity of Aerospace Systems is coming into light.
Controls and Dynamics
An aeroplane takes off with nose up, cruises with wings level and takes a turn with body rotated. All these manoeuvres require the pilot to control the aircraft. To design the control system, we need to understand the dynamics of the aircraft. Similarly, all aerospace systems need guidance, navigation and control (GNC) systems. You need a strong mathematical background for GNC expertise.
Controls and dynamics need to account for all the forces being applied to the body. Aerodynamics provide the forces due to flow of air, propulsion provides the propulsive forces and internal forces due mechanisms are given through structural simulations. Along with this, there are many structural, thermal and dynamic constraints. The GNC system has to be able to account for all of the above details.
Design and Systems Engineering
With four of the fields understood, we recognise the complexity in the design of the Aerospace Systems. Design and Systems Engineering connects it all together. To design an aerospace system, experts from all the fours domains need to come together. Systems engineer ensures smooth workflow of information between the different subsystems defined by distinctive fields.
Design and Systems engineer also ensure that the mission of the Aerospace design is being met. Generally, that means an optimisation problem is solved. For example, we may be designing lightest parachute. This exercise would need all divisions to work. Therefore, design engineer, communicate with experts from different fields and create mathematical models with their assistance. These models are then utilised to solve the optimisation problem.
In the end, all the five divisions together design an Aerospace System.
I hope you gained a little understanding of Aerospace Engineering. I'll urge you to let me know about other topics and questions you have related to aerospace engineering through the following form or you can leave a comment. I'll make sure to cover them in next few Monday Mentoring posts.