Computational Fluid Dynamics(CFD),A basic Fundamental.

CFD- computational fluid dynamics is one  the best method to assume the flow physics.Basically the fluid flow problems are governed by the conservation principle of mass,momentum and energy. These conservation principles get expressed in terms of mathematical equations.These mathematical equations involves a set of non-linear partial differential equations(PDE).The main problem arise here ,the fact is :-there are no generic theories available to solve these PDEs.

 Here comes the role of CFD, Before going into CFD concept,one must understand what is CFD ? CFD is nothing but the analysis of systems that involves fluid flow ,heat and mass transfer ,chemical reactions by help of computer based simulation. It is basically a computer based solving process by help of some algorithms.


All CFD codes basically contains 3 main elements:

    1) Pre-Processor

    2) Solver

    3) Post-Processor

Pre-Processor:-

The preliminary step of a CFD analysis is the Pre-processing step.It involves- Defining the geometry,Mesh(grid) generation,Selection of the physical and chemical phenomena that to be modelled, Defining the material properties,specifying the appropriate boundary conditions,etc.
Before proceeding to this one should have a brief idea of the physical problem which has been chosen.

Solver:-

CFD uses some solver to solve these numerical problems, there are generally three numerical solution methods.

 1) Finite Difference Method (FDM)

 2) Finite Volume Method (FVM)

 3) Spectral Methods

ANSYS Fluent solver uses Finite volume method to solve the computational problems.


How Does the numerical algorithm in CFD works?

 1)Integration of the governing equations of fluid flow over all the elements/control volumes of the domain.Then converting the resultant integral equations into a system of algebraic equations.Then the solver uses iteration technique to solve by taking some initial guess.There are various algorithm used by CFD solver these are : SIMPLE,SIMPLER,SIMPLEC,PISO etc. All these algorithms will be discussed in the future.

Post-Processing:-

The post processing part of a computational problem involves the output of the simulation results these are :-Contours,Streamlines,Temperature plots,Grid display,2D and 3D surface plots,Particle tracing,Animations etc.