1-D flow

$$\begin{eqnarray*} \rho_1 u_1 &=& \rho_2 u_2 \\ p_1 + \rho_1 u_1^2 &=& p_2 + \rho_2 u_2^2 \\ h_1 + \frac{1}{2} u^2_1 &=& h_2 + \frac{1}{2} u^2_2 \end{eqnarray*}$$