I've found another paper dealing with the phenomena presented in my OP,
that is the reduction of drag on a square cylindrical prism (3D solid) "bluff
body" by placement of a separate cylinder in the up-stream airflow.
This new find has the drawing showing the hypothetical best placement of
the main body and cylinder/plate in common with the first reference. It has
different graphics though. It's biggest drawback is that other than a brief
introductory paragraph it is in Japanese.
Here it is, you can get to the document by using the PDF button in the:
Read/Search Full Text section:
CiNii- Drag Reduction of a Square Prism
OK, does anybody know which of the many web-based translators will produce
a readable Japanese to English version?
(Note: I'm not 'net/web savvy enough to extract Japanese characters out of
a PDF to input to a translator.)
Edit:
Here is a list that includes other studies which may shed light on this
phenomena, most of them are also in Japenese:
CiNii Square Prism