Question

What do the two subscripts of stress tensors represent?

(a) Directions of stress and strain

(b) Directions of stress and normal to the surface on which they are acting

(c) Directions of strain and normal to the surface on which they are acting

(d) Direction of stress and the flow direction

I had been asked this question by my college director while I was bunking the class.

Question is taken from Governing Equations topic in portion Governing Equations of Fluid Dynamics of Computational Fluid Dynamics

Answer 1

The correct choice is (b) Directions of stress and normal to the surface on which they are acting

The explanation: The two subscripts of stress tensors indicate the direction of the stress and that of the normal to the surface on which they act. So, stress tensors give the location and direction of the stresses.