But I think that your statement about
Quote:
integrating the pressures......
probably leaves many readers none the wiser.
Keith's wisdom supersedes my writing with the brain only partly engaged ..
Folk should recall that fluid flows are about pressures. Pressure gradients and deltas generate fluid flow. Static and flowing fluids generate forces on things like engine bits (and wings, tails, fuselages, etc.) by exerting pressure on surfaces.
Pressure acting over a surface (area) results in a force. Depending on the net orientation of the bit of surface in question (in, say, an engine) the force associated with the fluid pressure will have a net forward or aft direction (and, mostly, a lot laterally .. with which we are not terribly interested).
When one adds up all the bits of forces so calculated, one gets a net thrust (forward or aft).
"Integration" is a mathematics buzzword which really just means "adding up all the little bits and pieces" in the calculation. It comes from the integral calculus which is a really neat way of doing a lot of this stuff but it's not necessary for the pilot folk to have any competence in the mathematics per se.