In this post, I’m going to continue the discussion I started in my Volume Integrals post, but we will move on to the discussion of double, or surface, integrals. The double and triple integrals show up in every term of the conservation equations when couching them in integral form, so they are extremely relevant in any discussion of fluids or thermal studies. I dealt with triple integrals first because they are intuitively easier to understand. The trouble with double integrals arises because we are dealing with stuff that flows through the control surface (CS), as opposed to trying to account for something just sitting inside of a control volume (CV). The main difficulty in the understanding of the double integral terms results from the elegantly inherent way that we account for whether stuff is coming into the CV, or going out of the CV.
Bringing you videos about science, math, and engineering