How to start learning CFD?
 

Hii , this question might seem real dumb, but its because I'm quite new to CFD.

I want to gain a level of expertise so that I can write my own codes. How can I do this? i mean what all books to read, and more importantly what all topics I should know well. Should I start with the Finite difference method?

If you are a student you should see if your university offers a course. What books you should read depends on which method(s) you want to learn about. Patankar's "Numerical heat transfer and fluid flow" is the standard first reference for finite volume methods. Ferziger and Peric's "Computational Methods for Fluid Dynamics" is also good. Writing a simple 2D structured finite volume code seems like a reasonable place to start.

I would also recommend, "An introduction to computational fluid dynamics" by Versteeg and Malalasekeara. If you are interested in high Mach number flows, then "Computational Gasdynamics" by Laney is also a good place to start. Other introductory books: "Using Computational Fluid Dynamics" by C. T. Shaw, "Computational Fluid Dynamics" by John D. Anderson.

Do you know how to write code? If not then start with a book or course in programming. Matlab is a good start, but eventually you will want to know C, Fortran, etc. An introductory course in programming will cover solving PDE's I would suggest starting there.

How difficult could it be if you already know good how to program with a couple of programming languages?

C/C++ Python Visual Basic

knowing a programming language is something, writing a code is something else. However, being familiar with a programming language is inevitable to start writing a code. I believe that writing a good code (even a very basic one) needs both experience and good understanding of CFD concepts. The former is of higher importance which I personally lack.

It depends how well you understand the physics and numerical analysis. Learning CFD is a life-long process. The more that you use it, the more you will learn.

Thanks for the answers.
Exactly. I have programmed for years with c/c++ but I have to refresh FD, and numeric analysis is something new for me. I have a lot of work. ;)

You need to read a book on numerical methods if you don't know about that, a book on aerodynamics if you don't know anything about that, and I'd suggest Andersons book on CFD, it gives a good intro to CFD and also guides you through making your own code for 4 different simple simulations (1-D Nozzle flow, Couette Flow, and supersonic flow over a wing, off the top of my head)