This is just a brief follow up on my previous entropy and engines videos while I work on an upcoming video about jet engine thermodynamics. I compare adiabatic, isothermal and free expansion of an ideal gas. Free expansion resembles isothermal expansion, but the entropy increase of the gas is reversible for an isothermal gas but is irreversible for a free expanding gas (ie expanding into a vacuum). Also it is possible to calculate the entropy increase of a shockwave in an ideal gas with a constant heat capacity ratio https://en.wikipedia.org/wiki/Normal_... They are just tabulated because the equations are cumbersome, and non-ideal behavior sometimes has to be included.

Previous Videos on Thermodynamics
Entropy and The 3 Laws:    • A Practical Guide to Entropy and Ther...  
Engines/Heat Pumps and Thermodynamics Processes    • Air Conditioners are Backwards Engines