Frictionally resisted adiabatic expansion

Since the downstream station was chosen arbitrarily, it follows that the required relationship between specific volume for a frictionally resisted, adiabatic expansion is simply ... 

The significance of the change in polytropic exponent with efficiency is brought out more clearly if we take the mth root of both sides of equation (14.22) to restate the equation defining the frictionally resisted, adiabatic expansion in the alternative form ... 

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