CFD AND ITS APPLICATIONS

Computational fluid dynamics (CFD) is an aspect of multiphysics system analysis that undertakes the simulation of the behavior of fluids and their thermodynamic properties using numerical models. Computers are used to perform the calculations required to simulate the free-stream flow of the fluid, and the interaction of the fluid (liquids and gases) with surfaces defined by boundary conditions.

The first attempt to calculate fluid flow was set forth by Lewis Fry Richardson, with applications for weather prediction. He envisioned a “forecast factory” that included 64,000 human “computers”. Each “computer” was positioned at tiered elevations around a spherical globe, occupying computational cells that corresponded to map locations, for northern Europe. His method involved inputting weather observation data to the corresponding grid locations and then solving the forward-stepping equations.

Usually, a simulation with mathematical programs grounded on CFD can be divided into three stages: pre-processing, simulation and post-processing.

Which are the stages of a CFD simulation?

Usually, a simulation with mathematical programs grounded on CFD can be divided into three stages: pre-processing, simulation and post-processing.

Pre-processing

In the pre-processing the parameters are defined: field of study (domain), geometry and mesh construction (domain discretization), physical and numerical criteria, among others.

CFD Simulation

In the simulation stage the equations which define the fluid dynamics are solved. Thereby, it is possible to achieve the variable values of discretized governing equations such as velocity, pressure and temperature.

The simulation is only possible due to the discretization of the fluid, usually through the finite volume method, which in turn allows for the Navier-Stoker equations to be solved in order to achieve the desired result.

Post-processing

Lastly, in the post-processing stage, it is important to analyse whether the result is coherent. In this stage the relevant data is extracted to enable its conversion into graphics and tables, thus allowing for further system analysis.

In this phase it is essential  the use of the knowledge acquired throughout the academic and professional career of the person in charge of the analysis, especially in the field of thermo fluid dynamics.

CFD allows the visualization of the fluid distribution in respect to the desired variable in different manners. In the case presented on Figure 1, the profile is attained for the velocity of a fluid within a combustion chamber, as well as the flow lines. It is also possible to simulate the flow through tridimensional videos and the observation of critical operation points in a system.

APPLICATIONS OF CFD

1. AEROSPACE & AERODYNAMIC APPLICATIONS

Aerodynamics and aerospace are the way that air moves around objects. The rules of aerodynamics explain, for example, how an airplane can fly. Any device moving through air reacts to aerodynamics. Aerodynamics planes, rockets, cars, trains, or gulf balls since air flows around cars.  Computational Fluid Dynamics (CFD) has become operational in designing and analyzing products in aerospace and surface transportation industries, including automobiles, trucks, boats, and even insects.

The application of CFD today has revolutionized the process of aerodynamic design. In the older days, people used to test their crafts in actual conditions. But then came the wind tunnels provided the privilege of testing any hand-made objects used for flying and driving by putting them inside a tunnel against the airflow.  This gave them more control over the conducted tests and more significantly reduced the risks related to real-condition tests. However, wind tunnels were too costly, and huge-sized wind tunnels were needed for giant crafts such as airplanes.

CFD has emerged alongside the wind tunnel and real-condition flight or driving tests as primary tools for analyzing the flow effect over the hand-made objects. Different industries nowadays use CFD to increase their outcome and lower their design costs.  The more renowned industries for using CFD in today’s world are the aerospace, aeronautical, and car industries. Companies such as Airbus, Boeing, and many others in the aircraft industry and car companies such as BMW, PORCHE, GMC, and many more are now using this powerful tool.

2.BIOMEDICAL APPLICATIONS

 In recent years, there have been rapid developments in biomedical and health research applications of CFD. It has been used to evaluate drug delivery systems, analyse physiological flows (e.g. laryngeal jet flow), facilitate surgical planning (e.g. management of intracranial aneurysms), and develop medical devices (e.g. vascular stents and valve prostheses). Due to the complexity of these fluid flows, it demands an interdisciplinary approach consisting of engineers, computer scientists, and mathematicians to develop the computer programs and software used to solve the mathematical equations. Advances in technology and decreases in computational cost are allowing CFD to be more widely accessible and therefore used in more varied contexts.

3.PETROLEUM REFINING APPLICATIONS

CFD has the important role in petroleum engineering applications such as studying optimization of bit performance, convective heat transfer between casings and annular fluids, flow in porous media like mud filtrate invasion, simulation of multi-phase flow for designing separators, cement displacement .etc.

4.SPORTS

Recently sports have came up as one of the beneficiaries of the CFD. CFD is used to design sports equipment such as javalene, Cricket Bats .etc.

Moreover recently in 2020 olypics Chinese swimmers won the Gold medals. They used Aero techniques to train swimmers especially in their positions. THe analysis was all done using CFD.