Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - Window screen used as a skin on vehicles sensitive to crosswinds ?

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Cd	02-26-2021 08:56 PM

Window screen used as a skin on vehicles sensitive to crosswinds ?

Has the topic of window screen used as a skin on vehicles been discussed recently ?
This provides a surface for air to skip over, but also one that allows crosswinds to pass through.

There is a large metal chainlink fence at my job.
It takes maybe 30 lbs of force to close it, yet even a moderate breeze will cause it to slide on its railing and slam shut.

I know some of you sail boats.
I had no idea that wind would have so much pull on such a small surface area.

freebeard

02-26-2021 09:59 PM

I've always wondered about this. Mainly for bellypans.

Quote:

Anisotropy
Anisotropy is the property of a material which allows it to change or assume different properties in different directions as opposed to isotropy. It can be defined as a difference, when measured along different axes, in a material's physical or mechanical properties An example of anisotropy is light coming through a polarizer. Another is wood, which is easier to split along its grain than across it.
More at Wikipedia

Years ago I posted a link on Ecomodder to a study that showed a cattle truck with round holes at the front of the sidewalls was better than the rectangular horizontal slots that are more common (at preventing suffocation of the livestock!)

Window screen is flexible. Were you thinking of using it for daylight openings?

It's all holes. Maybe a perf metal with some arbitrary hole size and spacing is optimal?

So many questions. When I was in high school and college I worked summers in a feed & seed mill. They had stacked graduated stainless steel screens about 4x6 feet in a shaker for sorting mill run into different seeds. hole sizes below an inch or so.

The place burnt down a decade or two ago.

Piotrsko

02-27-2021 10:10 AM

Aren't dimples on a golf ball massive screen holes?

M_a_t_t

02-27-2021 10:19 AM

I was actually thinking about how maybe you could use it on the belly pan to cover the exhaust. Maybe at speed the air would flow past while at slower speeds it would be able to breath?

Cd	02-28-2021 11:59 AM

Quote:

Originally Posted by M_a_t_t (Post 643330)

I was actually thinking about how maybe you could use it on the belly pan to cover the exhaust. Maybe at speed the air would flow past while at slower speeds it would be able to breath?

Like a breath of fresh air, I would breathe a sigh of relief, if the breathing would be improved by the window screen.

The good thing about window screen, is that even if it rips and falls from the underside of the car, it doesn't have enough mass to damage anything.

It would have to be replaced often though if driven on roads with lots of debris.

j-c-c

03-01-2021 08:56 PM

Quote:

Originally Posted by freebeard (Post 643304)

I've always wondered about this. Mainly for bellypans.

Years ago I posted a link on Ecomodder to a study that showed a cattle truck with round holes at the front of the sidewalls was better than the rectangular horizontal slots that are more common (at preventing suffocation of the livestock!)

Window screen is flexible. Were you thinking of using it for daylight openings?

It's all holes. Maybe a perf metal with some arbitrary hole size and spacing is optimal?

So many questions. When I was in high school and college I worked summers in a feed & seed mill. They had stacked graduated stainless steel screens about 4x6 feet in a shaker for sorting mill run into different seeds. hole sizes below an inch or so.

The place burnt down a decade or two ago.

I always thought the best everyday common material to have this property, was concrete, in that it has far greater strength in compression vs tension, approx 10:1.

aerohead

03-03-2021 12:16 PM

aren't ?

Quote:

Originally Posted by Piotrsko (Post 643327)

Aren't dimples on a golf ball massive screen holes?

Only if it was a 'whiffle' ball. Porous.
Dimples provide a critical roughening, to trigger transition to a turbulent boundary layer, off the clubhead, at around 110-mph.

aerohead

03-03-2021 12:26 PM

screen

Quote:

Originally Posted by Cd (Post 643300)

No porous surface can support airflow.
If the entire perimeter of the vehicle's underbody is 'dammed' ( airdams, rocker panels, and rear facia, dead air will be trapped within that footprint, and active flow will skip over ( under ) this stagnant, dead air, which travels along, like the forward stagnation bubble.
Cooling air, from the engine bay will contaminate this area. EVs have the advantage.

cRiPpLe_rOoStEr

03-03-2021 07:16 PM

There would be a lot of compromises rendering such approach unsuitable. Even aircraft that still resorts to a fabric skin have it sealed, not leaving much room for the wind to go through. And for a car, other matters such as thermal comfort may be accounted, so even though a skin that allows some air flow in a simpler vehicle without HVAC might seem good in a summer afternoon it would become a PITA during winter or rainy days.

j-c-c

03-04-2021 10:15 AM

Quote:

Originally Posted by aerohead (Post 643517)

Only if it was a 'whiffle' ball. Porous.
Dimples provide a critical roughening, to trigger transition to a turbulent boundary layer, off the clubhead, at around 110-mph.

And one reason "whiffle" golf balls are so suitable for enclosed indoor space golf ball practice, with its extremely high drag.

I personally can't vision what the benefits here are with pourous aero surfaces like fence/screen, but then, I here to learn.:D

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