For inviscid adiabatic flow, prove the relation 1 Dp p Dt in two ways: =-.u 1. by combining the energy and continuity equations; 2. by applying the isentropic relation p = const to a fluid element and recalling that V. u= 1 DV V Dt (This problem shows that inviscid adiabatic flow amounts to an isentropic process when we follow a given fluid element)