Question

Which of these terms in the momentum equation for θ – component represents the Coriolis force?

(a) \(\rho v_r\frac{∂v_\theta}{\partial r}\)

(b) \(\frac{\rho v_\theta}{r}\frac{\partial v_\theta}{\partial \theta} \)

(c) \(\frac{\rho v_r v_\theta}{r}\)

(d) \(\frac{\partial v_\theta}{\partial r}\)

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

Query is from Numerical Methods in division Numerical Methods of Computational Fluid Dynamics

Answer 1

Correct option is (c) \(\frac{\rho v_r v_\theta}{r}\)

To elaborate: The term \(\frac{\rho v_r v_\theta}{r}\) represents Coriolis force in the θ – momentum equation. Coriolis force arises due to the motion of the coordinate system taken. The term \(\frac{\rho v_r v_\theta}{r}\) represents the source or sink of θ -momentum.