please refer some good books which makes us understand the physical and mathematical meaning of meshing and numerics of both CFD and FEA
a good start would be:
More a tutorial but also useful : A Comprehensive Tour of snappyHexMesh - OpenFOAMWiki
Introduction to the Finite Element Method – Niels Ottosen & Hans Petersson
The Finite Element Method Set (Sixth Edition) – O.C. Zienkiewicz, R.L. Taylor and J.Z. Zhu
A First Course in Finite Elements – Jacob Fish, Ted Belytschko
Concepts and Applications of Finite Element Analysis – Robert D. Cook and David S. Malkus
[Finite Element Procedures in Engineering Analysis] (https://www.amazon.com/Procedures-Engineering-Prentice-Hall-engineering-mechanics) – K.J. Bathe (MIT)
Of course any PDF you can find for CFD and FEA via Google will help you understand the topic a little bit better.
For FEA, Meshing will play a role in almost every book that you can find since it is essential to understand how FEA (“FINITE Element Analysis”) works.
My FEA Series covers the basics of that, so you might also have a look at that one.
@power_users, feel free to add some more.
I will soon publish a dedicated page for this. So thanks for the question