CFD and its various uses

“Colour Picture” of the airflow around an F1 car. These pictures really mean a lot to an aerodynamics engineer, although this might seem like a beautiful “painting” for the layman

What is CFD?

CFD is a branch of fluid mechanics that uses numerical analysis and data structures to solve problems that involve fluid flows​ which are governed by the Navier-Stokes Equation​s… No, we are not going to be your professors! Let us keep things simple (Though if one plans to learn CFD to greater depths, they inevitably have to face this jargon. Can’t help it) So for the time being, treat CFD as a way to calculate the velocity, pressure, and other parameters of a fluid at various points in a fluid flow by solving a certain system of equations (basically the conservation of mass, momentum, and energy) using computers. Depending upon the situation, the computer could be your homie lappy or big boys like the PARAM SHAKTI supercomputing system here at IIT Kharagpur, capable of doing 1.66 PetaFLOPS!

CFD and Aerodynamics

Nowadays, CFD plays a major role in the aerodynamic development of vehicles (from cars to airplanes), wind turbines, tall buildings, bridges (you might want to watch this if you haven’t: Tacoma bridge), etc. Some of you might be surprised to know that CFD is used to improve the performance of golf balls too! We, at TeamKART, do a lot of CFD analysis. This is due to the following reasons:

  1. The cost associated (in terms of money as well as time) with traditional physical testing methods like wind tunnel testing
  2. It is simply impractical to make models of various parts, test them one by one and throw them away if optimization is not achieved
  3. All you need for testing models using CFD is a good PC.
  4. A lot of institutions and organizations might have little to no access to a proper wind tunnel facility.
CFD Simulation of an F1 car
CFD Analysis of Burj Khalifa, the world’s tallest building. The blue region behind the building is called “wake,” a low-pressure region generated by the obstruction of fluid flow by a body

CFD and Powertrain

Now, we discuss another application of CFD, i.e., the powertrain. Powertrain refers to the engine and the transmission of a vehicle and CFD has important applications in this field. Due to the various chemical reactions and rapid heat transfer happening in the powertrain components, especially the Internal Combustion engine, CFD has to be often coupled with various chemical reactions as well as thermodynamic mechanisms to be useful as a tool to analyse combustion and associated phenomena.

CFD Simulation of an internal combustion engine

Other CFD Applications

CFD is used very widely in almost all kinds of industry, from turbomachinery, chemical reactors, power generation, automotive sector, chemical manufacturing, polymer processing, petroleum exploration, medical research, and even in the food industry. Guess what, it can also aid in weather forecasting!! With the development of computers having enhanced computational power and memory, it is now possible to simulate fluids and heat transfers on a large scale. As a result today, fluid simulation is an essential tool to simulate meteorological phenomena, from daily short-term weather forecasts to long-term climate change. These large-scale fluid simulations are also useful in the study of geophysical flows.

CFD simulation of Covid-19 spread in an AC room

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TeamKART

TeamKART

Official Formula SAE team of Indian Institute of Technology Kharagpur.