Rotation
Now it is required that
Since angles Rotation or angular velocity of the element (about the z-axis) is defined as Combining eqns. 4.36 and 4.37 we have, Similarly we have for rotation about the other axes,
We see that
We now introduce another term Vorticity which is defined as twice rotation or This brings us to a class of flows for which vorticity (i.e., rotation) is zero. These are known as Irrotational Flows. These are governed by the equation, Subsections (c) Aerospace, Mechanical & Mechatronic Engg. 2005 University of Sydney |