You add energy to the flow mainly by direction changes. These barge boards have less direction change than a typical curved panel barge board. I don't think there is more surface area on the vertical bits either; maybe the strakes on the horizontal makes for increased surface area. However there is negligible increase in drag from skin friction.A-Bap wrote:On a fundamental level, there's much more surface area meeting the flow than with a standard bargeboard, and therefore more points of flow energization. Energizing air costs power.ringo wrote:I don't see anything to sugges that it is more draggy.
The frontal area isn't much more than the usual barge boards because of the multiple gaps.
most of the drag may come from vortices, but no real evidence exists to say how much of it is considerable drag.
It is something that would have to observed or investigated. I don't think we can assume it's very draggy. Increased Vortex drag is more plausible, but with the strakes being close to the ground, the ground will break the vortices.