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Computational Fluid Dynamics

Dr. Ugur GUVEN

Professor of Aerospace Engineering(Ph.D)Nuclear Technology Engineer (M.Sc, PA )

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What is Fluid Dynamics

Fluid Dynamics is the study of fluids (liquidsand gases) under various conditions to seehow they will behave.

Fluid dynamics allow us to examine theinteraction between solid bodies and fluids sothat their dynamics can be worked out forengineering purposes.

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Areas of Fluid DynamicsFluid dynamics encountered in everyday life include:

meteorological phenomena (rain, wind, hurricanes, floods,fires)

environmental hazards (air pollution, transport of contaminants)

heating, ventilation and air conditioning of buildings, cars etc. combustion in automobile engines and other propulsion

systems

interaction of various objects with the surrounding air/water complex flows in furnaces, heat exchangers, chemical reactors

etc. processes in human body (blood flow, breathing, drinking . . . )

Any physical process where fluids are involved

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Approaches to Fluid Dynamics

There are three approaches to fluid dynamics:a) Theoretical Approach

(The usage of Energy, Mass, Momentum equations)

b) Experimental Approach( The usage of experimental data for determining fluid behavior)

c) Computational Approach(The usage of Numerical Methods, Computer Programming and Computer

Simulation Software for Fluid Dynamics)

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What is CFD? Computational Fluid Dynamics (CFD) provides

a qualitative (and sometimes evenquantitative) prediction of fluid flows

CFD enables scientists and engineers to

perform numerical experiments (i.e.computer simulations) in a virtual flowlaboratory

real experimentCFD simulation

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Why Use CFD? Numerical simulations of fluid flow (will) enable architects to design comfortable and safe living

environments designers of vehicles to improve the aerodynamic

characteristics chemical engineers to maximize the yield from their

equipment petroleum engineers to devise optimal oil recovery

strategies surgeons to cure arterial diseases (computational

hemodynamics)

meteorologists to forecast the weather and warn of naturaldisasters safety experts to reduce health risks from radiation and

other hazards military organizations to develop weapons and estimate

the damage

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Examples of CFD

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Examples of CFD

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Examples of CFD (Other Fields)

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Examples of CFD (Manufacturing)

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Examples of CFD (Medical)

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Examples of CFD (Medical)

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Examples of CFD (Other Fields)

Smoke plume from an oil fire in

Baghdad

CFD simulation

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Experiments vs. Simulations

CFD gives an insight into flow patterns that are difficult, expensive orimpossible to study using traditional (experimental) techniques

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Experiments vs. Simulations

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Approaching a CFD Problem

CFD Problems must be approached with the followingmethodology:1) Problem must be defined using equations of FluidDynamics (such as the Navier Stokes Equations)2) Equations will have to be solved with numericalapproximation methods with as much iterationmethods as possible.3) FORTRAN or other scientific computer programminglanguages can be used to solve these fluid dynamics

equation with numerical methods.4) Fluid Dynamics & Heat Transfer Simulation Softwaresuch as ANSYS (FLUENT) or STAR is used to simulate thenecessary parameters graphically.

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CFD Analysis Process

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CFD Computing Power For detailed and realistic analysis of CFD

problems, often clusters of computers areneeded. Even with the computers below a CFDmodel preprocessing can take weeks.

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Quality of the Simulation in CFD

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Fluid Characteristics

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CFD Tools

Some popular CFD Software that you need tolearn are:a) GAMBIT for Drawing the System

b) FLUENTfor Processing the Results (ANSYS isthe name of the whole package)c) OPENFOAM for CFD applications in UNIXd) FEMLABfor Heat Transfer and FlowApplicationse) FEATFLOW for CFD applications in amainframe environment.