Here, four unknowns(u, V, W, p. We know the conservation of mass equation, +— --four equations Nonlinear, second order, partial differential equations #10 Heat Transfer Su Yongkang School of Mechanical EngineeringHeat Transfer Su Yongkang School of Mechanical Engineering # 10 Here, four unknowns (u, v, w, p.) We know the conservation of mass equation, ----------four equations. Nonlinear, second order, partial differential equations. = 0   +   +   z w y v x u