FLUID DYNAMIC
- 1. MAHENDRA TIWARI CSJMA14001390232 COMPUTATIONAL FLUID DYNAMICS 1 EXPERIMENTAL FLUID DYNAMICS (EFD) ANALYTICAL FLUID DYNAMICS (AFD)
- 2. 2 “A theory is something nobody believes except the person proposing the theory and an experiment is something everybody believes except the person doing the experiment” --Albert Einstein(1879-1955)
- 3. Overview:- What is CFD? Purpose and Aim How it works? Advantages Applications Limitations of CFD References 3
- 4. What is CFD? Computational fluid dynamics (CFD) is the science of predicting fluid flow behaviour of indefinite geometry. We are interested in the forces (pressure , viscous stress etc.) acting on surfaces. 4
- 5. We would like to determine the velocity field. (Example: In a race car, we are interested in the local flow streamlines, so that we can design for less drag) We are interested in knowing the temperature distribution. 5 16/03/2018
- 6. History of CFD 6 Since 1940s analytical solution to most fluid dynamics problems was available for idealized solutions. Methods for solution of ODEs or PDEs were conceived only on paper due to absence of personal computer. FLUENT, TIDAL, C-MOLD, GASP, FLOTRAN, SPLASH etc.
- 7. National Scenario in CFD: Educational / Research Institutes –IIT’s, IISc, BARC NAL, BHEL, SAIL, GTRE, Cummins, Mahindra, Birla group,GE, TCS etc. 7 16/03/2018
- 8. Why CFD ?? 8 Growth in complexity of unsolved engineering problem. Need for quick solutions of moderate accuracy. Developments in computers in terms of speed and storage. Efficient solution algorithms.
- 9. How it works? Analysis begins with a mathematical model of a physical problem. Conservation of mass, momentum, and energy must be satisfied throughout the region of interest. Fluid properties are modeled empirically. 9
- 10. 10 CFD process flow Pre - processing Solver Post -Processing Geometry Creation Geometry Scaling Boundary conditions Problem Specification Additional Models Numerical Computations Understanding flow with color, Line and Contour Data Average Values (h,Fd) Report Generation
- 11. 11 Governing equations Conservation Of Mass Momentum Conservation Energy Conservation
- 12. 12 Operation The flow region or calculation domain is divided into a large number of finite volumes or cells. Partial differential equations are discretized using a wide range of techniques: finite difference, finite volume or finite element. Algebraic equations gathered into matrices which are solved by an iterative procedure .
- 13. Advantages: Relatively low cost:- CFD simulations are relatively inexpensive, and costs are likely to decrease as computers become more powerful. Speed:- CFD simulations can be executed in a short period of time. Ability to simulate real conditions:- CFD provides the ability to theoretically simulate any physical condition. 13
- 14. Applications Electronics thermal analysis Designing of super duty vehicles like trucks , tempos etc.(based on thermal stress points) Thermal comfort in office environment 14
- 15. Limitations of CFD 15 Physical models CFD solutions rely upon physical models of real Processes Numerical Errors Round-off error Truncation error Boundary conditions
- 16. Conclusions: CFD is a powerful tool to solve complex flows in engineering systems. However: Extreme care should be taken while: Generating geometry and grids. Choosing flow model. Boundary conditions. Material properties. 16 16/03/2018
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