What is CFD (Computational Fluid Dynamics) ✦ Definition CFD is a computer-based tool used to simulate how fluids (like air, water, gas) move and interact with surfaces, heat, and each other. It a.pptx

What is CFD (Computational Fluid Dynamics) ✦ Definition CFD is a computer-based tool used to simulate how fluids (like air, water, gas) move and interact with surfaces, heat, and each other. It a.pptx

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  What is CFD?(Computational Fluid Dynamics) CFD is a computer tool that helps us model how things like air or water flow over objects, spread heat, and mix with other fluids — without doing real experiments. It allows engineers to visualize and predict: • How air flows over an airplane wing • How water flows through a pipe • How smoke spreads in a room • How blood flows in arteries
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  What happens insideCFD? • To understand that, let’s look at three basic ideas: 🔹 1. Fluid flow is governed by physics laws • Fluids obey the Navier-Stokes equations, which describe: • Conservation of mass (Continuity Equation) • Conservation of momentum (Newton’s 2nd Law applied to fluids) • Conservation of energy (Heat transfer, etc.)
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  2. We can'tsolve these equations directly for real-world shapes • These equations are complex, and there is no exact solution for most real-life problems like an aircraft, car, or turbine. • So we break the flow region (like around a wing)into small pieces called grid cells or mesh and solve the equations approximately in each cell.
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  What are NumericalMethods? They are mathematical techniques used to approximate solutions to equations when exact solutions are impossible. • Examples: • Finite Difference Method (FDM): Approximates derivatives using differences (used in structured grids). • Finite Volume Method (FVM): Divides the flow domain into small control volumes and applies conservation laws to each (most popular in CFD). • Finite Element Method (FEM): Used more in structural analysis but also in fluid flow problems.
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  What are Algorithms? Algorithmsare step-by-step procedures the computer follows to: • Set up the equations • Solve them iteratively • Adjust values until the solution becomes stable (called convergence) • For example: • Solving pressure and velocity in each mesh cell using an iterative solver like SIMPLE, SIMPLEC, or PISO.
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  Real-Life Analogy • Imagineyou want to know how water flows through a river: • In an experiment, you build a physical model and pour water into it. • In CFD, you build a computer model of the river. • Then divide it into many small blocks (mesh). • Apply the fluid physics equations to each block using numerical methods. • The computer solves the flow in all blocks using an algorithm, and gives you the speed, pressure, temperature at each point.
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  Why use CFD? •Saves time and cost over experimental testing. • Helps visualize flow fields (streamlines, pressure contours, etc.). • Enables testing of multiple design changes quickly. • Can be used in extreme conditions where experiments are difficult (e.g., hypersonic flight, nuclear reactors).
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  Key Industries UsingCFD Industry CFD Applications • Aerospace Aircraft wing design, drag prediction, shockwave analysis, combustion in engines. • Automotive Aerodynamics, thermal management, cabin airflow, engine combustion. • Civil Engineering Wind loading on buildings, pollutant dispersion, HVAC design. • Marine Ship hull design, propeller optimization, cavitation studies. • Medical Blood flow in arteries, airflow in lungs, medical device simulation. • Energy Wind turbine simulation, gas turbine analysis, cooling systems. • Chemical Industry Mixing in reactors, multiphase flows, chemical transport.
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  Common CFD Applications(Examples) Aerodynamics of Vehicles • Reduce drag on cars or aircraft. • Improve fuel efficiency. Internal Flows • Turbomachinery (compressors, turbines). • HVAC ducts, piping systems. Heat Transfer Problems • Cooling of electronic devices. • Thermal protection systems for space vehicles.
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  Multiphase Flows • Oil-water-gasseparation. • Boiling and condensation in heat exchangers. Environmental Flows • Air pollution dispersion. • Water flow in rivers and dams. Biomedical Flows • Blood flow through arteries. • Airflow in nasal passages.
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  Benefits of CFD •Provides detailed insight into flow behavior. • Reduces prototype testing and improves design accuracy. • Can be combined with optimization algorithms for better results. • Supports virtual prototyping and simulation-driven design.
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  Limitations of CFD •Requires powerful computing resources. • Numerical errors and convergence issues can arise. • Results depend on boundary conditions and turbulence models. • Still needs validation with experiments for accuracy.