Common Questions asked about CFD Modeling
What is Computational Fluid Dynamics (CFD)?
- CFD analysis is a technique of flow prediction using fluid mechanics, numerical methods, and computer science. This approach is also called CFD modeling. Because, it involves a lot of mathematical, numerical and physical approximations for real fluid flows in order to save huge simulation cost.
- This technique is widely used in many automobile, mechanical, process and chemical, aerospace industries, energy sector and weather forecasting. This is also called as a virtual experiment to predict flow physics instead of actually carrying out experiments in laboratories. Fluid flows (like air, water, and gases in atmosphere) have a lot of application in our real life and nature. Therefore, this topic has been an interesting subject for many engineers and scientists.
- CFD analysis is based on many interdisciplinary subject. Hence, mathematics, flow physics, and chemistry, advanced numerical method, programming skills, high-performance computing (HPC) are paramount for CFD modeling.
- In CFD analysis, computer science plays a pivotal role as it involves both CFD software and hardware. To solve complex real-world problems like tornado, weather forecasting, super-computers are required. Hence, in this fields, the importance of parallel computing (HPC), GPU and machine learning (artificial intelligence ) has been increased. Hence, many developed countries have been working to make more powerful supercomputers to proliferate research and developments activities for space, defense and weather forecasting
- CFD analysis is carried out with three major steps:
- Pre-processing: Geometry creation and meshing
- Simulation: CFD Solver setting and numerical simulation
- Post-processing: Results analysis of CFD data obtained from simulation
What are major applications of CFD analysis?
CFD analysis has applications in many industries to design or improve the system, or develop new products or services.
- Automobile and aerospace industries
- Cement, process and chemical industries
- production and manufacturing industries
- Turbo-machinery (fan, turbine, compressor, blowers, and pumps etc.)
- Thermal and nuclear power plant
- Combustion, fire, and environmental pollution
- Heating and ventilation of building, car, bus, and civil aircraft
- Weather forecasting
- Defense and space applications
- Biomedical applications
Which are popular soft-wares for CFD analysis?
Many CFD analysis softwares are available. Commercial soft wares are easy to learn for beginners as they provide a complete user guide, training materials with technical support. However, they have a high licensing fee. Some Open source CFD analysis tools (OpenFOAM , Code Saturn) are freely available, but CFD users cannot get detailed training materials. Hence CFD users take more time for learning.
CFD users can judge CFD tools by considering the following factors:
- Comprehensive Packages:
- Commercial CFD tools provide comprehensive packages. Geometry, meshing, simulation, and post-processing are avalaible in a single package. Hence, they are quite easier for beginners
- Open source solvers can not provide comprehensive package, So, they are difficult initially for CFD beginner
- Specialty :
- ANSYS FLUENT is one of the popular and multipurpose CFD solver f0r compressible and compressible flows
- CONVERGE is widely used in automobile industries for IC Engine modeling as it has zero meshing time
- Star CCM is widely used in automobile industries due to automatic meshing
- COMSOL is one more popular CFD solver for electromagnetic simulation. COMSOL has a LBM solver for battery or biological simulation.
- CFD Models: check models for turbulence, heat transfer, multi-phase flow, and reactive flow etc.
- High-performance computing (HPC)
- Some commercial CFD solvers can not support high-end simulation on HPC with unlimited cores
- For OpenFOAM solver, we can use unlimited cores available on HPC for simulations
- Customization of CFD solver
- Commercial CFD solvers provided limited customization in their solver
- Open source solvers are easy to customize. It is popular for research in academia
- Overall cost
- Commercial CFD solvers have a high licensing fee
- Open source solvers have no licensing fee
- Commercial CFD solvers have good GUI for results analysis
- Open source solvers have limited GUIs for post-processing
- Results Analysis and Validation
- Compare CFD results with experimental or practical data
- Select right CFD models available in the solver. No one can give 100% assurance that your CFD results are correct for complex cases.
- Check all the steps of simulations
How much time does an engineering graduate take to learn the basics of CFD modeling?
The learning of CFD depends on types and complexity of problems. The familiarity of commercial CFD tools like ANSYS FLUENT, STAR- CCM , COMSOL and CONVERGE takes 1 to 2 months. For open-source CFD solver like OpenFOAM, Code Saturn it will take 6 months to 1 year to understand solver setting and simulation of complex problems as it involves a lot of C++ programming.
Click here: How to install CFD Software for students?
Is it necessary to have programming skills for CFD modeling?
For an initial phase, good programming skill is necessary to understand how governing equations used to get numerical solutions. Programming skill will help for customization of functions in CFD solver like user defined functions (UDF) in ANSYS Fluent, COMSOL and OpenFOAM. If you want to develop a CFD solver from scratch then learn programming (C, C++, and shell) languages. Those are unable to code, then can use MATLAB.
What is the role of Mathematics in CFD modeling?
In fluid mechanics , heat transfer or complex flows, governing equations are in differential or integral forms. Hence, having a mathematical background is useful to understand complex terms and numerical modeling. Students can learn partial differential equations (PDE), integration, vector algebra, and numerical methods (FDM, FEM, FVM).
- Many complex flows like turbulent, multi-phase and heat transfer, having the knowledge of scalar and vectors is useful for physical understanding of complex equations. If you are familiar with equations in tensor forms, then you can understand OpenFOAM.
- Learn useful tensor operations and how they are implemented in OpenFOAM.
- Example: second order tensor in OpenFOAM.
What are the major steps to learn CFD from the basics to become an expert in CFD coding?
To become an expert in CFD coding, the following steps are important:
- Basic Subject knowledge: Learn basic governing equations for fluid mechanics, heat transfer and flow physics etc.
- Programming skills: C, C++, Python and MATLAB
- Numerical Methods: Finite difference method (FDM), finite volume methods (FVM) and their application on a variety of problems
- Advanced Programming Skills : geometry mesh interface, parallel computing, and post-processing GUI
- Validation of CFD results: Compare the your CFD results with experimental data and well-established CFD tools
- CFD Modeling of complex flow: heat transfer, turbulent flow, multi-phase flow etc.
What are popular books for CFD Modeling
There are many books available from basic to advance level. But you can read some popular books using Finite volume methods.
- J. T. Guan Heng Yeoh Chaoqun Liu, Computational Fluid Dynamics: A Practical Approach,Butterworth-Heinemann, Elsevier Publication,. 2018
For Intermediate User:
- H. K. Versteeg, W. Malalasekera, An Introduction to Computational Fluid Dynamics: The Finite Volume Method, Pearson Education Limited (2007)
For advance level you can read specific books and research articles as per scope of topics:
Click here: References for CFD, Flow and Machine Learning
How can I get a job of CFD Analysis in industries?
During your final project (B.Tech or M.Tech degree), if you take any project relevant to CFD analysis, then you will learn to learn CFD skills and application subject knowledge
- Some companies like ANSYS, COMSOL, and CONVERGE provide free licenses for academic purposes. Download the CFD analysis softwares from their official website and start learning from basic tutorials.
- Those CFD users are good in C++ programming, they can install OpenFOAM on Linux platform. Learn how the programming structure of CFD solver is developed. To develop a simple flow solver, strong programming skills and basic numerical methods are essential. You can take a coding based CFD projects.
Based on you project work, relevant companies can select for core jobs available in automobile, mechanical, process or chemical industries, and aerospace engineering. Prepare some fundamentals equations in fluid mechanics and CFD modeling.
Click here : Check your interview, Important Questions for CFD Engineer
What technical competencies are asked by industries?
The technical competency and skill of CFD software play crucial for CFD Modelling of industrial problems. As per the type of CFD projects, the CFD engineers need to update knowledge and experience for different fields like multi-phase flow, turbo-machinery, combustion, heating, cooling, and I.C. Engine modeling. Each industrial problem requires different skills and subject background. Therefore, CFD users need to train for both technical and software skills.
What some industries use CFD analysis for product development?
CFD analysis is very useful to carry out parametric studies for different design parameters for complex design of products. Design optimization is mainly carried by using this method to achieve the objectives of industries such as low pressure drop in ducting, high heat absorption by heat exchanger, particle deposition rate in cyclone, prediction of flame pattern in boiler and furnaces. Some industries can not afford their CFD modeling and they collaborate with service industries.
What is the future scope of CFD Analysis?
A CFD Analysis widely in many automobile, mechanical, process and chemical, and aerospace industries. Whenever Industries carry out research and innovation of new products and services, then CFD analysis will be used in industries. Different job opportunities will be created as per demand of work, skill and subject expertise. Due to an increase in computational power and well established CFD softwares, simulations have become affordable for both medium and large-scale industries.
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Is experimental or practical knowledge of flow essential for CFD Analysis?
Without understanding of basics in engineering subjects (like fluid mechanics, multiphase flow and combustion), physical or actual flow physics, and limitations of CFD models, CFD anlysis has no meaning. You will never be confident in your CFD results. Initially, you can grow professionally by learning CFD sofwares but you can not ensure your designed flow system will work without any practical issues.
- Practical problems may be beyond of CFD modeling due to unavailability of materials, limitation in fabrication or manufacturing, high cost and experimental situations
- Some problems may be easy to model but difficult to carry out experimental analysis
- Some problems like porous media flows or flow over sands are easy to do experiment but difficult to model in CFD simulations
Validation of CFD results with experimental or field data from industries is important for credibility of CFD results. Based on experimental or practical data, CFD modeling is rectified.
Overall, practical knowledge of fluid or heater transfer with strong basics of engineering subjects will help students to bring confidence in CFD results.
Do not be only skilled engineers for CFD tools but also have strong base of engineering subjects including practical understanding flows.
Why small-scale industries cannot afford CFD Modeling?
Small-scale industries that cannot afford the cost associated with CFD analysis which is 5 to 20 times of design cost as per handbook and correlations. The major cost in CFD analysis is contributed by the capital of commercial software and man-hours of experts. Some Open source CFD solvers are freely available, but CFD users take more time for learning.
Is a Ph.D. degree in CFD Modeling a good option for a future career in academia and industry?
PhD in computation fluid dynamic (CFD) along with experiment is the best option to get good publication easily. Ph.D. helps intensive analysis of CFD results as well as report writing skills. Research papers with the validation of numerical results with experiments are easily accepted for reputed international journals. A number of publications will help for post-doctoral and academic jobs. CFD modeling is widely used in industries for the analysis and design of systems. Hence having a CFD background is always a privilege for future jobs.
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Which are the best institute for learning of CFD modeling?
Many academic and non-academic institutes in India to provide training on CFD modeling. See their official website, experience and background of the trainer. CFD analysis or modeling is a very vast field. As per complexity, the subject knowledge and skills change. Hence, specialized or experienced CFD trainers are useful for some complex topics. Many online materials are freely available for basic levels. Note your requirement relevant topics for CFD analysis. For example, some process industries need training for multiphase and reactive flow. Automobile industries prefer training for IC engine modeling.
Click here: CFD Online Classes at Affordable Rate