rain aero-meter LOL - Fuel Economy, Hypermiling, EcoModding News and Forum

pgfpro · 10-06-2009, 12:42 PM

The other day I was coming home from work and noticed the on-coming traffic's rooster tails from the water on the road.

Then all of sudden a Prius goes by and I noticed it had very small rooster tail. as in practically nothing? So I chalk it up as coincidence but then another Prius goes by with the same result. So now it has my interest. I keep a watch for another 40miles and sure enough every car with a aero design has a very small rooster tail.

I know this isn't scientific but it sure was interesting.

basslover911 · 10-06-2009, 02:23 PM

I love looking at the wheel wells when its raining. You can see how much trapped air is in there in some cars, while in others (usually sport cars) all the excess water simply goes backwards "sticking" to the fender and door.

When I took the mirrors off of my Mazda, I noticed that my side windows were super clear when raining since the mirror didn't block off airflow- another not so scientific observation but cool non the less (and removing the mirrors did improve my mpg by about 3-4mpg's, so seeing it work in the rain is kind of magical)

srortega · 10-06-2009, 03:14 PM

I need new tires that don't stick out past the wheel wells, when it rains, it gets the side of my car so dirty. Someday I will get a new car.... someday...

Old Tele man · 10-06-2009, 04:23 PM

...can you say "...empirical..." data collection and analysis? Sure, you can!

MetroMPG · 10-06-2009, 06:09 PM

I've done this too.

Definitely qualifies for the "You know you're an ecomodder when..." thread!

Added. You know you're an ecomodder if...

aerohead · 10-06-2009, 07:41 PM

There's a stretch of local loop around Denton which has an extensive backdrop of dense trees which provides the perfect contrast to watch these water-entrained wakes.I've been known to just pull over and watch.------------------------ With a small telescope or medium telephoto lense,you can detect dusty bow and stern wakes off 18-wheelers on dry days if the sunlight is just right.----------- Yea,I know,I need help!

Cd · 10-06-2009, 07:54 PM

Ever look behind the cab of a trailerless 18 wheeler after a rain ? The wind swirls around over the roof and you can see it travel upwards behind the cab.
It resembles steam rising from the chassis. ( You can see it vortex )

I find that the best conditions for this are right after a rain when the roads are still wet and there is lots of humidity in the air.

Metro : I posted this a long while ago on that thread. Now I'm going to have to hunt it down.

sprinterdellacasa · 10-29-2009, 08:04 PM

As a kid I used to draw pictures of what I thought would be the airflow around a car, kind of like a "this is going fast" kind of thing. I'm still fascinated by what might be called "fluid dynamics", but I don't know enough math to get past basic college stuff.

Toyota had an ad for the 80? Corolla, a hatchback kind of sporty-ish car. I loved the look of the car, and the ad had the car driving in water (rain?) with the shot taken with a slightly slower shutter speed, making the droplets around the car kind of blur together. I googled it briefly just now but I only got shots of Toyotas driving through puddles. This ad was a picture of the car going at speed, with the roostertail and everything.

F1 racing - I remember watching the Williams BMW cars in F1 - the air went straight up from the rear wing. Not that any other F1 car was different, but at the time I was rooting for them.

sdc

Christ · 10-29-2009, 08:43 PM

Quote:

Originally Posted by sprinterdellacasa

As a kid I used to draw pictures of what I thought would be the airflow around a car, kind of like a "this is going fast" kind of thing. I'm still fascinated by what might be called "fluid dynamics", but I don't know enough math to get past basic college stuff.

Toyota had an ad for the 80? Corolla, a hatchback kind of sporty-ish car. I loved the look of the car, and the ad had the car driving in water (rain?) with the shot taken with a slightly slower shutter speed, making the droplets around the car kind of blur together. I googled it briefly just now but I only got shots of Toyotas driving through puddles. This ad was a picture of the car going at speed, with the roostertail and everything.

F1 racing - I remember watching the Williams BMW cars in F1 - the air went straight up from the rear wing. Not that any other F1 car was different, but at the time I was rooting for them.

sdc

If you're interested in fluid dynamics, a basic understanding of algebra and some collective geometry skills will get you by for the most commonly used calculations.

Other than that, it's just a science that requires alot of thought about "the path of least resistance" and how flow reacts to resistance.

It's only called fluid dynamics because if you can flow through it, it's a fluid.

That, of course, includes both gasses and liquids. There are also some things called non-newtonian fluids, which basically means that they can transfer between a solid or fluid state based on input.

More here!

Old Mechanic · 10-29-2009, 09:52 PM

I use rain-x on all my windows. It's neat watching the drops. When you get in a draft they bounce around and go in circles sometimes.

Another neat thing is when you are following a bus on a 2 lane road with grass growing tall on the side of the road, watching the movement of the grass behind the bus gives you a good idea of where the draft is working best.

regards
Mech