Quote:
Originally Posted by lunarhighway
this is what wikipedia has on te naca intake
looking at this example it's hard to overlook the similarities between two vg's and a naca intake.
so it's my understanding that they work on the same principle where the vg's reënergise the boundy layer by drawing in air from outside the boundry layer and naca's draw do the same but draw in air below the boundty layer, and the skin.
this suddenly made me think that an upswept lip spoiler ofte found on sporty hatchbacks, but also on car with very low drag quoefficients could be an every simplified vg, epsecially since the once that can be suspected to be there for true aero reasons are often rounded and heigher in the middle
here a picture on my string of thoughts that might make more sence...
but then that last configuration looks like this test autospeed did
on their hoda insight and they recorded no benefit. but of course the insight is already highly optimised and might not need any band aid somutions as it's basic form is already so good... and all the separation angles are very optimised |
Thanks lunarhighway for the data on the NACA duct.I have only seen military versions of them,and the sidewalls diverge at such a small and gentle angle,it's hard to imagine how there would be any separation,however,without any radii at the skin interface,I can see how air could spin into the void.---------------- And yes the similarity between the two devices almost makes one believe they were conceived from the same stock,forming male,and female counterparts simultaneously.------------------------ I still hit a mental glitch,with them used at the very back of a form,without another trailing surface for the flow to re-attach to.----------------- If the wake is turbulent and without major vorticity,my understanding is,that this is about as good as we can hope for,and any additional drag reduction would necessarily come from lengthening the vehicle while reducing the cross-sectional area,to reduce the wake itself.------------------------------------- If the saw-toothing can actually reduce drag,then its a minor coup! Lower drag from shorter vehicles is a very desirable target.Stranger things have probably happened.I'd like very much for it to work!