How/why a taller exhaust stack on an offset?

[Tallbald]

New here and have been looking around about OK Joe Highland modifications for clues to a better machine. Some have found a taller stack, in the form of an aluminum extension, gives better draw of air into the firebox. Not sure I understand how/why that's the case. I seem to remember from school that taller industrial stacks draw better at factories but I thought that was because they reached higher in the atmosphere and the faster moving air (wind) at the top created a low pressure effect that drew more air up through the stack, like low pressure on top of a plane wing. Please teach me. Thanks. Don.

 

[daveomak]

You are correct... The top of the stack is in less pressure than the base... Therefore a draft is created...

 

[forkin pork]

I don't mean to jump in on my mentor daveo, and yes he is 100% correct, but "Sensay" does it really matter if you have a long pipe extending upward at 200ft up .... as apposed to an extension at 3ft off the ground. Does it not come down to longer is better in any case?