Question

An equation for the conservation of kinetic energy can be obtained by ___________

(a) the product of momentum equations and mass

(b) the product of momentum equations and velocities

(c) the product of continuity equations and velocities

(d) the product of continuity equations and mass

I have been asked this question in an interview for internship.

My query is from Incompressible Flows topic in section Incompressible Flows & Compressible Flows of Computational Fluid Dynamics

Answer 1

The correct option is (b) the product of momentum equations and velocities

The explanation: Momentum is the product of mass and velocity. Kinetic energy is half of the product of mass and the square of velocities. Therefore, by multiplying the momentum equation with the velocity and further simplifying the resultant equations, we can get the conservation equations of kinetic energy.