Mist trail "wind tunnel"

[aerohead]

Originally Posted by California98Civic

So, even if the flow patterns had changed somewhat, with mirrors and without them, the total power lost to drag was not significantly reduced by the changes?

Correct,no difference.
Ford reported on this over twenty years ago during their Probe concept car series R&D.
When GM did their PNGV Precept,around 1999,they found that all the features drag on the car amounted to Jack Diddly.Nothing to fret over.
If you take the average of your mirrors height and width and multiply that value by 6,this is the distance behind the mirror where the air has essentially recovered from the disturbance.
For their frontal area,the mirrors drag is statistically insignificant compared to the overall drag.And its disturbance to the free stream should be dampened by the time the air makes it to the C-pillars.

[ChazInMT]

The tuft testing and patterns of residue left after misty rain do not tell the full story of what the air is doing around a vehicle. While interesting to look at and indicative of what the gross patterns of air may be doing around the car, they are but footprints left by what's going on with the really important overall airflow around the car which extends out to several feet in all directions. So just like looking at the foot print of a T-Rex may be interesting to see and study, it is by no means the be all/end all for what the animal is really all about.

Just thought I'd put this here to maintain a bit of perspective regarding the airflow very close to the skin of the vehicle.

[freebeard]

Reducing Windnoise / Raingutter Fillers

Even if it won't reduce drag, there's still wind noise.

[California98Civic]

Who knew that a small amount of dust stuck to the roof could cause turbulence? But here is a photo of mist on the roof of my car after a short drive on a very foggy morning. The sun has just broken through:



The "stain" is in the center left, just above a crescent-like semi-circle created by the coffee cup I had momentarily laid on the roof before I noticed this interesting mist effect. The "stain" is rough, made by dust that suck to some dried coffee I had spilled there the day before as I got into the car. Extending from left to right, as the airflow, you can see how the rough spot seems to have generated turbulence that dried a widening area of the roof aft of it in the airflow.

Just an interesting pic, I thought I'd share.

[euromodder]

I've seen the effects of dimples a mere millimeter (1/24 inch) in height, added to the front of a car , so I'm not surprised.

(On the rear end, 1mm would be too shallow to really have a noticeable effect.