Module 5: Reynolds Transport Theorem
  Lecture 15: Equation of motion
 
 
It is shown that,  where is the strain rate.
  • In the case of a static fluid,  at any location in the fluid. In a moving fluid, however, :

(Fig. 15c)
  • If fluid is inviscid,
    And, , as in the case of a static fluid
  • For a 3D flow, there are two  and one  on a plane, as shown below

 
(Fig. 15d)

There are sign conventions:   
x: direction of normal to the plane or the direction of the area
y: direction of shear stress