[Stoves] Concentrators in ND TLUDs

[Boll, Martin Dr.]

Paul, Paal, Crispin and all,

A lot of time ago I asked myself if "diaphragm" by  T-LUDs could be an even adequate name instead of concentrator-disk. 
- That expression would lay the accent on restraining the flow, which I guess, could be as well of importance as concentration.
- Just a thought on the function, not a suggestion to change the name of the disk-.

Regards
Martin

P.S. the cross-section ratio:  hole to metal-disk is _always_ 1 to 1 ? 
 - That means: The radius of hole- and disk-diameter differ by the factor root of 2 .

By all described T-LUDs  I saw this ratio; or are there other/different ratios ?
Is there a _simple to understand_ explanation for that ratio, beside "that works best" ?