However, due to the mixing process, there is a net increase in the entropy of the system.
Stream thrust: Mass flow: Stagnation enthalpy: Solving for
If it is not clear which value of velocity is correct, the second law of thermodynamics may be applied.
One possible unreal solution for the stream thrust averaged velocity yields a negative entropy.
Another method of determining the proper solution is to take a simple average of the velocity and determining which value is closer to the stream thrust averaged velocity.