Hi All,
Unfortunately I'm not an aero engineer (yet), but that is where my passion is. I've been studying some notes I have from my Aero/Thermo class, and taking other classes related to aerodynamics. I am not one to 'just accept' the use of equations, so I've been spending some time to try to understand, in English, (gamma1)/gamma.
I think this is the most interesting thing I've ever studied in 2+ degrees of college and a number of jobs. So I was driving home from work yesterday thinking about this, and thought of a pressure cooker. Here is what I came up with:
Gamma (ratio of specific heats) is basically showing the percentage of energy that goes to volumetric expansion of the gas when heated, so it takes more energy to heat a gas at constant pressure than at constant volume (hence the pressure cooker  if gamma=1.4, then it takes 40% more energy to heat the same air to the same temperature in an open pot).
(gamma1)/gamma seems to me like a ratio of the (energy of expansion) to the (energy to raise temperature), or energy absorbed by the gas.
I think (gamma1)/gamma comes up first as a way to equate total temperature to Mach number. I came up with the idea that Mach number is like the ratio of (kinetic energy of a moving gas) over something like the (expansion energy of the gas at that temperature), or the kinetic energy associated with pressure wave propagation. If the gas is moving with same kinetic energy associated with a pressure disturbance, M=1.
Got to run  would love to have a conversation about what is actually going on with these equations, rather than just moving numbers and letters around a page to find an answer.
Any links or book reference would be greatly appreciated too












