Brian Hall : You could just as easily call it Directional non-heating, by pinching the barrel, Ianto Evans calls it Eccentric Placement or Eccentric Positioning, you can have
a cool side to the drum, with less heat radiated off of the barrel on that side as a way to protect the Exposures, whatever they are, a door way, a vertical wooden post,
or even just a near wall with 2X4 studs behind that Sheetrock!
We also set the barrel to the side a little to make a slightly larger air flow pattern on the side of the barrel directly over the Transitional Area to help carry along the
descending hot exhaust gases directly to the transitional area !
So-Yes, You have understood it correctly (Directional Heating means something else to a H.E.V.A.C. Engineer )
Setting the barrel to make a cool side should never pinch or narrow the space available above the Transitional Area ! Lack of a good flow to the transitional area, and a
too small opening in the transitional area are two of the biggest reasons for problems with your RMH ! Always make sure both your Heat Riser and your Barrel are level
Success has a Thousand Fathers , Failure is an Orphan