| Re: TGV Aerodynamic Noise |
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Group: alt.planning.transportation · Group Profile
Author: Stephen SprunkStephen Sprunk Date: Sep 7, 2008 11:11
Laurence Sheldon wrote:
> Hans-Joachim Zierke wrote:
>
>> JR-West and JR-Central: Complete covers for the joints between cars.
>
> It is interesting to note the difference in fuel consumption, if myou
> drive a big truck with an adjustable fifth-wheel (the "hitch" on the
> back of a semi-truck tractor).
>
> If it is moved toward the front of the truck to minimize the gap between
> cab and trailer fuel mileage is noticeably improved--even if the tractor
> is fitted with "spoilers" at the sides and top.
>
> No, I don't have any numbers at hand...
>
> I wish I did.
While not directly applicable, MythBusters did a study on whether
tailgating trucks reduced fuel consumption for the follower. Even at
100ft, the effect was noticeable, and as they closed to 5ft, it reached
~90%% reduction in fuel consumption. They tried 2ft, but the constant
adjustment of the throttle to keep the car at exactly that distance
overpowered the reduction in air resistance -- however, that would not
apply to a coupled trailer (or train). The closer the objects get, the
more energy you save, and by a surprisingly large amount.
This makes me wonder if RRs should investigate some way to cover the gap
between freight cars/containers and improve trains' fuel economy even
more. It also has serious implications for faster passenger RRs that
are still using old-style cars with gaps between them rather than
articulated cars or permanently joined cars with covered joints.
S
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