There are several areas of interest where CFD is used.
Even I am an amateur, trying to learn many things in CFD...
Through out the learning phase, I strongly felt that before jumping into the software it's important to take up some productive course highlighting the ideas and things happening in the background of the software.
Knowing these will give us a better understanding of how the flows are solved..
Then trying to solve basic problems of your interest using different options and analyzing and comparing the results thoroughly will make things more clear.. likewise as we continue further to work on numerical simulations of more complicated problems, we will get an opportunity enhance our knowledge and understanding further..
first you may need focus on one specific tools tutorial, then start making your own simulation. in the meantime, the best tutor could be the mistakes. troubleshooting of mistake could brings you a myriad of invaluable hints. However, studying CFD foundation prior to would be a must.
To become an CFD expert, It can be simple with some hardness.
It must know firstly:
1- The fluid mechanics, to be familliar with the equations and types of fluid( Governing equations, laminar-trans-turbulence, compressible and incomprehensible, newtonien...)
2- The numerical methods, to know which methode are better to resolve your problem ( high resolution , first order, simplec....)
After that, you must choose a specialty (Aerodynamics, rehology....), and practice tutorials for any CFD code.
Without forgating the most important thing, the understanding of the physical phenomena.
2. Study about the numerical solution-procedures ( initial value problem and
boundary value problem of the differential equations)
3. Study deeply about Numerical Methods.
4. Study deeply the different programming languages, such as Fortran, C, and
C++ etc.
5. Obtain a good idea on how to discretize Navier-Stokes equation (for Fluid flow)
and other equation using the Finite Volume method, Finite difference method, and
finite element methods.
6. Obtain a good idea on how to generate a grid system for a particular domain of calculation ( your interest).
7. And then solve many problems by implementing appropriate boundary conditions and initial conditions.
8. Obtain knowledge on how to visualize your raw data using other software (
free software: Paraview)
9. Get the knowledge to justify whether your result is correct or not; it is very important!!
10. Study the tutorial manual of a Commercial software, such as ANSYS ( not free) or OpenFOAM ( free)
11. Check how different boundary and initial conditions affect the result of a set governing equation. Different boundary conditions will give you a different solution but governing equations and geometry are the same !!
Finally, you have to repeat the above steps along with other related matter for several months for several problems, which will make you an expert in CFD gradually!! Anyway, it is not so easy to become an expert of CFD for a short time !!
To become an expert of CFD, you have to learn many issues, which are mentioned partially in the above section !! Good luck!!
Speaking from my experience, the main elements are mathematics, programming, and physics (fluid mechanics at least)!
I am aware that this is really broad and no one can cover the whole but at least one should try to achieve a good level at each one of them.
For mathematics, consider that it is not only about numerical methods, it is also about the theoretical part and even functional analysis. You may find very fascinating shortcuts and overviews of your work if you know more about the mathematics behind your numerical method and your physical model.
For me, a CFD expert is one who can solve the problems computationally with a precise result. So, he/she must have a good background and knowledge of mathematics, numerical methods, and a particular field such as fluid mechanics, heat transfer, chemistry, and so forth. He/she must do some real projects in industry or other places. Moreover, an expert needs time for having experience.
The process of becoming an expert has curves like a hockey stick.