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madmax98
madmax98 New Reader
9/21/21 10:27 a.m.

I've noticed a lot of new cars have this really really sharp crease running down the side. I can't see this making manufacturing easier, and it doesn't look that good. Could it be for aerodynamic reasons? How would that work?

 

67LS1
67LS1 Reader
9/21/21 11:18 a.m.

It also might be to strengthen the panel. Less opportunity to "oil can". Like a bead rolled in a flat panel.

 

SVreX (Forum Supporter)
SVreX (Forum Supporter) MegaDork
9/21/21 12:54 p.m.

Individual tastes vary. 
 

I guarantee they didn't put it there because the majority of their buyers think it is ugly. 

Robbie (Forum Supporter)
Robbie (Forum Supporter) GRM+ Memberand MegaDork
9/21/21 1:13 p.m.

The roof and front and rear windshields on a car make a pretty good interpretation of the top of an airplane wing. This does create a low pressure zone above the cabin, and there can be some pretty interesting aero effects 'around the corners' of the car. Also, mirrors are usually a mess aerodynamically, so I see this kink as possibly helping prevent side air from getting sucked upward, and keeping it separate from the mirror. 

 

Appleseed
Appleseed MegaDork
9/21/21 1:19 p.m.

Remember when cars were slab sided?

madmax98
madmax98 New Reader
9/21/21 1:28 p.m.
Robbie (Forum Supporter) said:

The roof and front and rear windshields on a car make a pretty good interpretation of the top of an airplane wing. This does create a low pressure zone above the cabin, and there can be some pretty interesting aero effects 'around the corners' of the car. Also, mirrors are usually a mess aerodynamically, so I see this kink as possibly helping prevent side air from getting sucked upward, and keeping it separate from the mirror. 

 

I do think it has something to do with that.

It's not just for looks, otherwise it wouldn't be this sharp. It's a really sharp kink. You could bruise pretty badly if you bump into it. 

And I thought about it stiffening the door, but it also doesn't need to be this sharp. Many cars have a bend there for this reason, but it's more of a curve.

asphalt_gundam
asphalt_gundam Reader
9/21/21 2:29 p.m.

Gut reaction is thinking of years ago when the headlights got all pokey to the sides on some cars....reason was noise reduction caused by how the air moved around the mirror. Could it be to reduce wind noise at the window???

dculberson
dculberson MegaDork
9/21/21 2:40 p.m.

I think it looks cool. I bet Audi's designers think it looks cool.

Robbie (Forum Supporter)
Robbie (Forum Supporter) GRM+ Memberand MegaDork
9/21/21 2:47 p.m.

Another thing to consider is cross wind stability. When thinking aero it is easy to only think of the case where air flows straight at the car. But in cross wind situations that isn't true. Cross winds can cause instability by increasing lift at the rear more than the front, and that kink may slow that down.

WonkoTheSane
WonkoTheSane GRM+ Memberand UltraDork
9/21/21 3:20 p.m.
67LS1 said:

It also might be to strengthen the panel. Less opportunity to "oil can". Like a bead rolled in a flat panel.

This is my vote.  You can have a significantly thinner metal to make up the skin if you have creases like that.  That 300 above probably has significantly thicker metal in the doors, and a much more rigid structure to support that.

madmax98
madmax98 New Reader
9/23/21 8:58 a.m.
asphalt_gundam said:

Gut reaction is thinking of years ago when the headlights got all pokey to the sides on some cars....reason was noise reduction caused by how the air moved around the mirror. Could it be to reduce wind noise at the window???

Very possible. 

I guess we won't really know unless we see some tunnel testing or CFD. 

madmax98
madmax98 New Reader
9/23/21 8:59 a.m.
dculberson said:

I think it looks cool. I bet Audi's designers think it looks cool.

It's not just Audi, it's kind of universal now. I see it on civics, Kia, even SUV's.

madmax98
madmax98 New Reader
9/23/21 9:10 a.m.
WonkoTheSane said:
67LS1 said:

It also might be to strengthen the panel. Less opportunity to "oil can". Like a bead rolled in a flat panel.

This is my vote.  You can have a significantly thinner metal to make up the skin if you have creases like that.  That 300 above probably has significantly thicker metal in the doors, and a much more rigid structure to support that.

That was my initial guess, but then I did the "knock" test on my friends Audi and it did not sound thin. Not very scientific, I know lol.

I guess if that was the case then you would see "bruiser" creases like this all over the car, or in more locations.  Some of these cars are NOT light, so weight reduction doesn't seem to be a priority there. Additionally, this potentially costs more to manufacture, and has more quality control issues because of the extreme sharpness (more rejections). That cost couldn't be mitigated by cheaper thinner steel sheets (they don't seem thin anyway).  

Also, the particular location leads me to think it's for aerodynamic reasons. I mean, why near the mirror and not in the middle of the door height?!

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