Momentum Equation

The forces upon the control volume sum up to

$$\sum F_x~=~p_1~A_1~-~p_2~A_2~+~p_1~(A_2~-A_1)~=~p_1 ~A_2~-~p_2~A_2$$ (3.113)

Substituting in the momentum equation, we have,

$$~p_1 ~A_2~-~p_2~A_2~=~-\rho~V_1^2~A_1~+~\rho~V_2^2~A_2$$ (3.114) (3.115)

(c) Aerospace, Mechanical & Mechatronic Engg. 2005
University of Sydney