RG is filled with people running various commercial CFD codes. If this is all you ever do (running someone else's code), you will never learn anything. Yes, learn from others, but create something new yourself. Choose some particular aspect (separation, laminar/turbulent transition, non-Newtonian fluid, whatever) and create a solution targeting that area of CFD. Don't take the wide path of the easy way with everyone else. Take the narrow and steep path less traveled because the view is much better. http://dudleybenton.altervista.org/projects/CFD/supergirl.gif

I am old school CFD researcher; hence, my view point on this issue is old school. For those persons not well acquainted with coding that is closer to machine level, i.e., those not very familiar with memory management and more complicated data structures, I recommend regular FORTRAN. FORTRAN memory and data structure management is easy to grasp, and if you utilize a compiler flag like check bounds, the compiler will identify many memory problems for you. When you code equations in FORTRAN (in either the 77, 90 or 95 releases), your coded equations will look a lot like those in your notes. Debugging is rather easy either by the use of old fashioned print statements or by the use of debugging software. Reading other person's code is an entirely different topic. Unless you are familiar with the compiler or interpreter used to develop the code, you are in for a lot of work. Good luck.

Yeah Douglas! I too am old school, having written a half-million lines of FORTRAN, including several CFD codes. Learning it the hard way is so much better than popping open a can. I never use commercial software because what I wrote is better. Read all about it here... https://read.amazon.com/kp/embed?asin=B082FPFN1M&preview=newtab&linkCode=kpe&ref_=cm_sw_r_kb_dp_62VKNBPAMRH9557B28JX

Thanks for reply Douglas and Dudley. I prefer using C++ because a lot open source CFD code is written by C++. By the way I don't mean which language recommended for CFD coding. I mean which project do you recommend for practice just for improving coding skills not just CFD for fun.

I haven't used FORTRAN in many years because C is so much more convenient and powerful. Interactive applications are very problematic in FORTRAN. I discuss the differences between FDM, FVM, and FEM in the book plus there is free code available for each. As I explain, one method is not universally superior to the others, as is often presented in the literature. There are groups of problems where one method is preferable over the others, so choose wisely and don't just use what is popular online at the moment.