- Sir Isaac Newton gave the world the basic equations of motions which govern the motion of objects, but it wasn't until French engineer Claude Navier and Irish mathematician George Stokes developed the Navier-Stokes equations, which allow for accurate calculations of an object's velocity, pressure, and other characteristics at any and all points in time. These equations effectively allow scientists and engineers to write programs that can be used to simulate the flow of any fluid from one point to another.
Originally, CFD was born out of the need to use computers to analyze different airfoil shapes in order to determine which ones were better for airplanes. This occurred during the 1930s, but CFD as a branch of science did not begin to take off until the 1960s due to the improvement of computing power. CFD is now studied at many major universities and is applied to many fields of science. - All CFD analysis and simulations are separated into three distinct parts: pre-processing, processing, and post-processing.
In the pre-processing phase, a problem is defined. This problem is the "what" of what is to be studied. Once the problem is defined, conditions must be defined for the problem. These are known as initial conditions. Then, boundary conditions must be defined to act as boundaries for the problem. In this phase, it is also decided how this problem will be studied, such as what method of discretization, what numerical methods to use, and what programming language to use.
In the processing phase, the computer code used to solve the problem at hand has been written and is compiled. This phase is mainly user-free because the computer is performing hundreds and thousands of calculations in order to simulate the problem at every step in time. The end result of this phase is a large collection of data.
In the post-processing phase, many thousands of calculations have been performed and data relevant to the study has been produced. This data is then filtered and converted into meaningful data. - CFD has many benefits to companies and to researchers. Some argue that using a computer to simulate flow using CFD is chapter and easier than building the required machinery, tooling, and equipment to manufacture a test part and then test it physically. CFD also produces accurate results and data for every point of time and thus can be used to completely track even a single particle of a fluid from point A to point B.
- One of the major issues of relying on CFD-produced data is verification and validation. Before a new CFD code or results can be trusted, it must first be verified that the codes are calculating the right equations, and then the results must be compared with physical, real-world tests in order to validate the accuracy of the calculations. Because of this, CFD will not and cannot be used as a sole source of data for the time being.
Another major hurdle of using CFD is the limitation due to computing power. Supercomputers are getting more and more powerful every year, but real complex CFD problems, such as problems with moving boundaries and many different flows, require computing power that, while it is possible today, is not fast enough to solve in due time. - Current research topics that use CFD are atomization problems, the process of turning streams of fluid, such as fuel, into tiny droplets of fuel in order to enhance combustibility. Research in atomization may allow for better designs of fuel injectors that can improve fuel efficiency of cars.
Future research topics in CFD are using it to analyze biological systems. The human body is one such system, and our veins, blood vessels, neural paths, etc, are extremely complex with many forks, branches, and sizes of different orders. Research into this field can be used to develop drugs that can combat diseases through advanced and accurate targeting, or understand biological processes better to improve human healthcare.
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