Question

Which of these statements is correct?

(a) Body force term in the momentum equation is non-linear

(b) Rate of change term in the momentum equation is non-linear

(c) Convective term in the momentum equation is linear

(d) Convective term in the momentum equation is non-linear

The question was asked in an interview for job.

My question comes from Incompressible Flows in division Incompressible Flows & Compressible Flows of Computational Fluid Dynamics

Answer 1

Right option is (d) Convective term in the momentum equation is non-linear

For explanation: The convective term in the momentum equation is given by \(\frac{\partial(\rho u_i u_j)}{\partial x_j}\). Where, ρ and u are density and velocity respectively. This term is a non-linear term. The rate of change and the body force terms are linear.