This manuscript is prepared for the aim of facilitating research activities in the area of transitional flows specially in gas turbines. It can be used by many reesearch scholars for further studies in this area of studies. In fact transitional flows has been attempted by a lot of researchers since past 100 years, and so far no general solution has been found for this problem because of its peculiarities. So it is of great importance that further studies to be carried out in this context. This book can be used as a initiative for this purpose.