Wind Buffering / Buffeting via Windows or Sunroof

[BBP]

Really there isn't, I always drive with my windows up and only open my windows for car parks.



The car defaults to drawing in air from outside which is filtered so why increase your fuel consumption by driving with the windows down.



Why should they change the design of the car to suit a group of people that can't be flapped adjusting the windows to suit their application? The vast majority of people drive with their windows up all the time.

The Golf is one of the only two cars in Australia that get 4 stars for forward visibility. Changing the A pillar and surrounding areas would compromise this.
The car is aerodynamic to minimise fuel consumption, changing it to suit the few people that like to drive with the windows down would compromise this.

How about the few people that want to drive with the windows down compromise instead and buy a weathershield or crack open another window?

My apologies, I didn't know you had conducted a survey and found only a few people ever drive with their windows down and the vast majority of people drive with their windows up all the time. What rubbish.

Anyway, the relevant point is that if other manufacturers can do aero efficiency and minimal buffeting then VW should be able to as well.

[Maverick]

Some good points there. I didn't know about the Golf being one of the two cars in Australia with a 4 star forward visibility rating - that's cool, and always great to have some quantifiable measurement.

http://www.drive.com.au/Editorial/Ar...eID=62121&vf=1

Holden's Commodore is one of 29 cars to get the lowest rating in a world-first study into the visibility afforded drivers by today's new cars. By JAEDENE HUDSON.

Improvements in crash safety have led to a design flaw in some cars that could obscure the driver's view of pedestrians or vehicles, an NRMA study says.
The first-of-its-kind blind spot study tested 138 cars using lasers and computers to assess the visibility they afforded drivers.

None achieved the maximum five-star rating and 80 per cent scored just one or two stars, indicating poor frontal visibility.

The reduced visibility is a result of the pillars on either side of the windscreen being made thicker to improve occupant protection and achieve favourable crash ratings.

"It is quite possible that someone could quite easily turn into the path of an oncoming car in a roundabout, a pedestrian or a motorcyclist [due to poor vehicle design]," Robert McDonald, the NRMA Insurance head of research, said.

The motoring group picked popular vehicles in segments of the market from city cars to four-wheel-drives and commercial vehicles. The best-selling Holden Commodore was among 29 cars - including two other Holdens - that scored just one star in the car blind spot rating.

Other one-star performers include the Toyota Yaris sedan, Audi Q7 soft-roader and BMW 1 Series.

Honda, a brand that performs strongly for pedestrian impact protection according to independent NCAP testing, fared poorly with Odyssey (now superseded), City, Accord and Legend models, which all scoring only one star.

Holden defended the Commodore's poor performance in the NRMA study.

"The VE Commodore has been designed to accommodate the latest safety technology to protect occupants if crashes do occur," a Holden spokesman, Jonathan Rose, said.

"We do not believe the blind spots are more significant than other large cars."

The cars rated best for forward visibility were the Volkswagen Golf and Citroen Picasso, which each scored four stars.

Mr McDonald acknowledged that makers faced a difficult design challenge combining safety with visibility, but he called for better driver sight lines.

"Modern vehicle design has improved the safety of cars for drivers and passengers remarkably in recent years," he said.

"But manufacturers may need to help drivers [by] striking a better balance between crash safety and visibility. It is a concern that in some cars a pedestrian or cyclist can be lost in a blind spot from as close as nine metres and a driver can lose sight of another vehicle from about 20 metres."

The NRMA testing involved rotating a laser 180 degrees from the driver's seat to determine where the line of vision was broken by the roof pillars.

I wish it were easier to have a discussion about the aerodynamics, but I find it very hard to find any information about the aerodynamic efficiencies of various cars, and even more difficult to find uniform measurement practices.

I don't see why you would do anything other than some rudimentary testing with the window down especially when nearly everyone drives with them up. Aerodynamics to me is about getting the air over the car with minimal drag, if you want a car where you can open the window without any buffeting you have to compromise on the aerodynamics when the windows are closed which means the car uses more fuel.

Holden and Ford both have cars that are not smooth on the sides around the side windows like the Golf is, I guess they figure most of their customers like to have their knuckles dragging when cruising so making the car more efficient would alienate their customers.

[Maverick]

My apologies, I didn't know you had conducted a survey and found only a few people ever drive with their windows down and the vast majority of people drive with their windows up all the time. What rubbish.

I conduct the survey every day, the only cars I see with the windows down are some tradesman, smokers who have it down or just cracked enough so they can flick their butts out the window, cars without air-conditioning and very few others.

Anyway, the relevant point is that if other manufacturers can do aero efficiency and minimal buffeting then VW should be able to as well.

Volkswagen do have fantastic aerodynamics and do extensive testing of the cars to minimise drag. They probably spend more time in wind tunnels than the other manufacturers if you look at the designs of their cars and how clean the lines are.

If you don't like an aspect of the car because you choose to drive with the windows down that's too bad, they are catering to the majority who drive with them up. There is a solution to your "problem" and you can fit a weather-shield from VW parts, you can adjust other windows, harden up or buy another car.

[G-rig]

Holden and Ford both have cars that are not smooth on the sides around the side windows like the Golf is, I guess they figure most of their customers like to have their knuckles dragging when cruising so making the car more efficient would alienate their customers.

Bogans usually have the window down and their arm hanging out as obviously their cars interior isn't comfortable enough to contain them.

That or they are abusing other drivers or smoking.

[team_v]

My apologies, I didn't know you had conducted a survey and found only a few people ever drive with their windows down and the vast majority of people drive with their windows up all the time. What rubbish.

Anyway, the relevant point is that if other manufacturers can do aero efficiency and minimal buffeting then VW should be able to as well.

I'm going to side with Mav on this one.
When on the road, the number of cars with windows down are severely outbnumbered by the cars with windows up.
I never have my windows down, especially when i have aircon as there is no need.

I believe forward visibility and a 5 star safety rating is a better use of design than having to re-design a car to reduce buffeting which can be reduced by lowering another window.

As said above, most of the people who have their wiondows down are either illegally litering with cigarette butts or illegally having their arms/feet out the window.

[G-rig]

People probably think they are saving on economy having the windows down and aircon off, but it's probably no better considering the worse drag and aerodynamics.

[Corey_R]

I don't see why you would do anything other than some rudimentary testing with the window down especially when nearly everyone drives with them up. Aerodynamics to me is about getting the air over the car with minimal drag, if you want a car where you can open the window without any buffeting you have to compromise on the aerodynamics when the windows are closed which means the car uses more fuel.

Yes, I totally agree. My comments about having data available is more so that we could discuss with some actual fact in relation to BBP's comments:

Anyway, the relevant point is that if other manufacturers can do aero efficiency and minimal buffeting then VW should be able to as well.

There are HUGE differences in aerodynamic efficiency between modern vehicles, even within the same manufacturer - but almost no one publishes things like 'Drag Coefficient" (Cd) etc. So whilst I disagree that other manufacturers are producing cars are aerodynamically efficient as the Golf (based on the fact that the Golf doesn't have any wind noise with all windows closed until over 180kph, and as you've noted, the side of a Golf is much smoother than Commodores and Falcons etc), without specific data from the manufacturers or independent tests, it's really hard to actually discuss this point any further (or to any worthwhile conclusion).

I'm going to side with Mav on this one.
When on the road, the number of cars with windows down are severely outbnumbered by the cars with windows up.
I never have my windows down, especially when i have aircon as there is no need.

Agreed. I'm not sure that anyone who drives with their eyes open could honestly claim that more people drive with their windows down than up.

[Maverick]

Yes, I totally agree. My comments about having data available is more so that we could discuss with some actual fact in relation to BBP's comments:

I'm not sure how anyone could given there is no way to test for every variation of wind and driving conditions. At least with Cd it can be done in a scientific manner but testing with the windows down, with different numbers of people in the car, different adjustments to seats, different tolerances to noises and so on is never going to be possible (and I can't see anyone ever trying to put together a way to try and measure it).

There are HUGE differences in aerodynamic efficiency between modern vehicles, even within the same manufacturer - but almost no one publishes things like 'Drag Coefficient" (Cd) etc. So whilst I disagree that other manufacturers are producing cars are aerodynamically efficient as the Golf (based on the fact that the Golf doesn't have any wind noise with all windows closed until over 180kph, and as you've noted, the side of a Golf is much smoother than Commodores and Falcons etc), without specific data from the manufacturers or independent tests, it's really hard to actually discuss this point any further (or to any worthwhile conclusion).

I found some info on wikipedia but the Cd is only part of the equation when you're looking at how the air flows over the car's body and can't really be used to compare anything meaningful.

For example
Mark V GTI has a Cd of .32 with flush glass on the side. (Very little wind noise)
EF Ford Falcon (1995) has a Cd of .31 with recessed windows on the side. (I had a EFII Fairmont Ghia and this had heaps and heaps of wind noise)

The AU Falcon Wagon has a Cd of .341 and the Sedan .295

[BBP]

We seem to be getting bogged down in a lot of garbage about Cds, wind tunnels, lazy window operators and casual observations being passed off as fact.

No one has suggested that some people drive with their windows down all the time. That's obviously not true. However, Maverick has suggested that "the vast majority of drivers" drive with their windows up "all the time", ie. they never have their windows down while driving. Again, that is patently nonsense.

The original post in this thread complained about buffeting when the windows are open. Whether that is for 5mins per year of driving or more is not the issue. The issue is that it happens a great deal (according to the original poster) in the Golf when other manufacturers can create designs that are still sleek but don't cause excessive buffeting.

[G-rig]

Once you're going too fast it's too noisy and windy anyway, like when you go onto the freeway it's not worth having the windows down.

It's nice to have them down if you're going slow and it's a nice day but with the pollution it's not really worth it anyway half the time.