Question

Viscous forces fall into which kind of the following forces acting on a body?

(a) Pressure force

(b) Tensile force

(c) Body forces

(d) Surface forces

The question was asked in semester exam.

I'm obligated to ask this question of Governing Equations topic in section Governing Equations of Fluid Dynamics of Computational Fluid Dynamics

Answer 1

Right choice is (c) Body forces

For explanation I would say: The two types of forces acting on a fluid are body forces and surface forces. Body forces are the forces produced by the fluid element itself. Surface forces are the one acting on the fluid elements. Viscous forces act on the element and it comes under surface forces.