Question

Which of these terms represent convection in the momentum equation?

(a) \(div(u\vec{V})\)

(b) \(div(\rho \vec{V})\)

(c) \(\nabla .(u\vec{V})\)

(d) \(div(\rho u\vec{V})\)

This question was posed to me by my school teacher while I was bunking the class.

Query is from Momentum Equation topic in division Governing Equations of Fluid Dynamics of Computational Fluid Dynamics

Answer 1

Correct answer is (d) \(div(\rho u\vec{V})\)

For explanation I would say: : From general conservation equation, the convection term is div(ρuΦ). For momentum equation, \(\Phi=\vec{V}\). So, the convection term in momentum equation is div(ρu\(\vec{V}\)).