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-   -   Automotive Aerodynamics (video series) (https://ecomodder.com/forum/showthread.php/automotive-aerodynamics-video-series-31047.html)

graysgarage 01-25-2015 12:21 PM

Automotive Aerodynamics (video series)
 
Hey guys,

I recently started a video series on automotive aerodynamics. During my research for each episode, I am often directed to this forum. So I thought I'd share my findings, enjoy!

www.youtube.com/watch?v=quDLzxmJl5I

https://www.youtube.com/watch?v=IFDZCIYe3RY

https://www.youtube.com/watch?v=LNnrY65-u-k

https://www.youtube.com/watch?v=AwD-UCd22Vw

Cd 01-25-2015 02:56 PM

Welcome !
Great to have you here.

graysgarage 01-25-2015 05:39 PM

Thank you, I look forward to any input and constructive criticism (suggestions) for future episodes

freebeard 01-25-2015 08:07 PM

Wow!

Quite a contrast between the garage (the one with the oriental rug on the floor. Can you get your car in there?) and the water tunnel (how many horsepower does that consume?) How do you get access to the water tunnel? Will you graduate and have it go away or do you have a permanent job there.

Did you see Yoshi Suzuka's work before it disappeared from Youtube?

I notice in Automotive Aerodynamics Future Episode Preview! you are soliciting models for testing. I built this in 1995, but I'd let you thrash on it:
http://ecomodder.com/forum/member-fr...re5624-vw1.jpg

Anyways, I guess I know where the next few hours are going, even though it's sunny outside. :thumbup:

2000mc 01-26-2015 03:14 AM

Can you measure forces in the water tunnel? If so, do you see expected increases / decreases in drag, when adding spoilers onto models?

MetroMPG 01-26-2015 12:32 PM

Great idea for a video series!

My initial suggestion, in this era of shortened attention spans, is on episode length.

I'm only partway through one (surprise: I chose the shortest one to view first... then again, that's because I should be working :) ) and it's fantastically info dense! If your goal is a seminar-type program (and I suspect it is), that's fantastic. But if your goal is widest viewership, it may be a drawback.

But now I know what I'll be doing for another couple of hours in the near future.

Obvious suggestion (if it hasn't been made yet): examination of some DIY drag-reduction mods, as found throughout our aero subforum.

Also: welcome to the forum!

Darin

bluesteel93 01-26-2015 12:46 PM

Awesome! Only watched the first video so far but looking forward to the rest!

MetroMPG 01-26-2015 12:52 PM

Briefly sampled a few more. Just fantastic - this thread is going on the front page.

(FYI, future replies to this thread bump it to the top of the list.)

HydroJim 01-26-2015 01:48 PM

I'm in between classes right now so I only watched the first 5 minutes of the first video but the series looks awesome!

Cd 01-26-2015 04:52 PM

Is it possible to add miniature tufts to the car models for tuft testing, or is water too dense to show this accurately ?

( I'm currently halfway through the first video, so i may have missed any tuft testing if you did it later in the series. )

aerohead 01-26-2015 07:44 PM

video series
 
Welcome!
All smiles here!:)
The idea and the work is great.These images speak volumes.I can't think of a better way to share.
If I could get it into public school curriculum I would.Consumers would have a very concrete conception of what was happening around their vehicle as they drove.The higher Reynolds number stuff really tells the tale.(tail?)
Can't thank you enough,and look forward to future releases.:thumbup:

dirtydave 01-26-2015 09:15 PM

HAHAHAHAHA me and my girl have a at home movie night where we both take turns picking a movie to watch for a "free" at home date night she is going to get a shock from this!!

California98Civic 01-26-2015 10:46 PM

Quote:

Originally Posted by dirtydave (Post 465550)
HAHAHAHAHA me and my girl have a at home movie night where we both take turns picking a movie to watch for a "free" at home date night she is going to get a shock from this!!

She must really love you, man. :)

dirtydave 01-26-2015 11:07 PM

This is why we take turns! lol

Cd 01-27-2015 11:46 AM

I found this 1/10 scale Civic hatchback.
1/10 scale is too large to fit in the tunnel, correct ?
http://www.rctech.net/forum/attachme...int-rc-061.jpg

redneck 02-02-2015 03:39 PM

.

Here's another one he did with the solar car in a wind tunnel.

https://www.youtube.com/watch?v=BHeVEKCObKU


>

OBD1Kenobi 02-02-2015 04:59 PM

I would definitely love to see how some of the more popular cars that are generally used for hyper milling stack up aerodynamically in wind tunnel testing. Very awesome videos!

benphyr 02-07-2015 08:18 AM

Thank you,

For all those of us without aerospace degrees and without access to wind tunnels and water channels this gives us the chance to vicariously be there and learn from your experience. Thank you greatly.

Subscribed so as to get any future updates,

benphyr.

p.s. I am down the road in Hamilton. Are you interested in visitors to your "shows" or testing or garage from ecomodders in the neighbourhood?

redpoint5 02-07-2015 08:15 PM

I enjoyed watching and suggest the following:

1. Reduce the length of each video by 25%. Spend less time on the intro and the exit from each idea, and instead just present the idea. In the first video, too much time was spent revisiting which cars are being tested, and which books were used to gleam the info. That sort of material can be added in the notes to the video instead of occupying the valuable meat of the info.

2. Develop an elementary intro to aerodynamics that discusses things like why attached flow is desirable, and how various high and low pressures develop and what those forces do to the vehicle.

3. Break the ideas up into smaller segments. This will help to reduce the intro video length. An independent video can explain how hydrogen bubbles are produced for those that are curious, but hydrogen bubbles don't have anything directly to do with aerodynamics.

I think the mistake most (uniformed) people make when conceptualizing aerodynamic shape is that they think in terms of cutting through the air. People already know through experience that a sharp blade cuts through objects better than a blunt object, and so their focus is drawn to separating the air at the front of an object while neglecting the other aspect of bringing the fluid back together again. This focused attention at the leading edge is likely why roof racks appear to the public to be designed with aerodynamics in mind, while the trailing transition is neglected.

I'm curious if very small aerodynamic changes can be observed and/or measured at small scale using your equipment. On Ecomodder, people add moon discs or wheel spats, and it would be neat to visualize the change that makes, or have data to quantify the drag reduction (or even increase).

bluesteel93 02-07-2015 08:45 PM

I'm also interested in a segment that covers belly pans. It's kind of cool being able to see the slowed down flow of bubbles underneath the car when you show the pulses of bubbles.

BrandonMods 02-07-2015 09:03 PM

I would be interested in seeing flow alongside of the vehicle after seeing the addition of wheel farings, and the vertical spoilers on bumpers and pillars.

Shawn D. 02-26-2015 02:08 PM

Great stuff, graysgarage! I have a Bachelor of Aerospace Engineering and have experience in wind tunnels and water channels (actually, water tables, but the same principle, of course) and appreciate you making these videos easy to understand for non-engineering types.

vadimr4 02-26-2015 03:07 PM

Flow visualization for minivan
 
These are great videos. Would love to see the flow studies for a minivan (ie Town & Country).

bluebunny 02-26-2015 04:44 PM

wowzers! Thanks so much for donating this valuable info to us! I am busy streamlining a camper trailer design, and working on some aero mods of wifey's mini-van. Your illustrations sure help reenforce my intuitions and previous research. Thank you!

PaulB2 02-27-2015 12:50 PM

Thanks for these videos, they really help.

I'd be interested in seeing the car rotated some. Most of the time, due to wind, the air does not flow straight from front to back, but crosses at some angle, if I am not mistaken.

I'd also like to see some commentary about the size and length of the rear wake, and how that affects the drag. I got the impression that sometimes a rear spoiler increases the drag, and sometimes it decreases it, and wondered why.

Cd 03-07-2015 05:27 PM

New video up ! Nice and to the point, and very informative.


https://www.youtube.com/watch?v=byA_tp0DINc

Thanks for posting !

Cd 03-13-2015 07:30 PM

https://www.youtube.com/watch?v=5UdROEOUyvg

New video posted of a 6th generation Civic.
The videos are now concise, and too the point. ( Bravo ! )
Another thing I was glad to see was a side by side comparison of the tests. ( at the end of the video )
Overall, a much more professional quality to the video.

I found it really interesting that the mid spoiler was functional on the 6th generation Civic. I wonder how much of an effect it had with a 5th generation model though, since the angles of the rear glass are quite different.

Thanks to this video, I can see why that a 6th generation car would have a higher drag than a 5th generation.

Thanks for posting !

nimblemotors 03-13-2015 09:31 PM

In the first video you wanted to correct misinformation about aerodynamics.
I haven't noticed anything that points out any misinformation that you've corrected.
Could you make a video specifically for this purpose?

graysgarage 04-08-2015 12:49 AM

Hey everyone,

Thank you for the feedback. I'm new to making videos and am still learning how to best shoot, edit, and present the information.

If anyone has models they would like to send me, anything in the 1:18-1:10 scale please send me an email.

Also, if anyone has questions or specific requests, please email me. You can find all my info on my website graysgarage.ca

I don't check forums very often, so this is the best way to reach me.

Thank you for the support!

New video btw

https://www.youtube.com/watch?v=vzMe1e9fE50

slipknotsv 04-18-2015 12:01 PM

amazing very nice idea. aerodynamic miniature :thumbup:

gumby79 03-05-2016 01:29 PM

Cda test request for a 91 Dodge"brick" Ram
 
Helow
[QUOTE=graysgarage;474540]Hey everyone,

Thank you for the feedback. I'm new to making videos and am still learning how to best shoot, edit, and present the information.

If anyone has models they would like to send me, anything in the 1:18-1:10 scale please send me an email.

I just purchased the only model for a 73-93 Dodge PU 1:43 scale. You said larger 1:18 to 1:10 is preferred, However, in the old stack of bricks design Dodge 1;43 is all i could find. The new trucks are every where in the proper scale


http://rover.ebay.com/rover/0/e11070...xe=exe,ext=ext
Also, if anyone has questions or specific requests, please email me have you added the link for this.?. You can find all my info on my website graysgarage.ca good info hear thank you

I don't check forums very often, so this is the best way to reach me.
you tube didn't get a response Eather
Thank you for the support!

My hope is that i can buld an accurate 1;43 removable canipè. To sind with the truck. For TESTING will pm you for an address to sind to

freebeard 03-08-2016 04:52 PM

1/24th is headed the wrong way. 1/3rd to 1/5th is best-er.

OP most recent post is still the solicitation at Permalink #29. Perhaps aerohead could suggest whether a fluid with less viscosity like rubbing alcohol or more viscosity like melted coconut oil would be better at 1/43rd scale.

gumby79 03-09-2016 06:19 AM

Was hopeful that my body type and year range could have its Cd info populated the newer dodge is available in 1:10 '73-'93 body I have only ben able to find in 1:43.
In one ofvhis videos he was able to 3D print a model that was not available.
Can anyone find the stock. Cd. CdA ect. Ect. For a '91 dodge D250. Sorhat I can so my % gain on Cd from down hill cost down testing mpgs show 27% FE improvement =54% improvement in drag reduction
What do you guys/gals think??

freebeard 03-09-2016 02:44 PM

Quote:

Sorhat I can so my % gain on Cd from down hill cost down testing mpgs...
This part makes my head hurt.

rumdog 03-09-2016 10:24 PM

Ha me too freebeard i was making a funny face trying to decifer it.
54% geez thats a big drop in drag. My cap is a similar shape, i was guessing 1/4 to 1/3 reduction in drag, but would be happy to be wrong!

aerohead 03-12-2016 01:48 PM

viscosity
 
Quote:

Originally Posted by freebeard (Post 508657)
1/24th is headed the wrong way. 1/3rd to 1/5th is best-er.

OP most recent post is still the solicitation at Permalink #29. Perhaps aerohead could suggest whether a fluid with less viscosity like rubbing alcohol or more viscosity like melted coconut oil would be better at 1/43rd scale.

We'd need a kinematic viscosity in order to calculate the Reynolds number,and from that determine the flow velocity to generate the critical Reynolds number based upon the scale of the model.
Texas Tech used as small as 1/24-scale in their water tunnel.
At very small scale we risk cavitation as low local pressures force a phase change in the working fluid.

aerohead 03-12-2016 01:54 PM

CdA
 
Quote:

Originally Posted by gumby79 (Post 508688)
Was hopeful that my body type and year range could have its Cd info populated the newer dodge is available in 1:10 '73-'93 body I have only ben able to find in 1:43.
In one ofvhis videos he was able to 3D print a model that was not available.
Can anyone find the stock. Cd. CdA ect. Ect. For a '91 dodge D250. Sorhat I can so my % gain on Cd from down hill cost down testing mpgs show 27% FE improvement =54% improvement in drag reduction
What do you guys/gals think??

I don't know if the data has been offered.
The D-100 1/2-tons were around 31.5 sq-ft frontal area.
I'd estimate the Cd at around 0.525.

aerohead 03-12-2016 02:09 PM

27% fe
 
Quote:

Originally Posted by gumby79 (Post 508688)
Was hopeful that my body type and year range could have its Cd info populated the newer dodge is available in 1:10 '73-'93 body I have only ben able to find in 1:43.
In one ofvhis videos he was able to 3D print a model that was not available.
Can anyone find the stock. Cd. CdA ect. Ect. For a '91 dodge D250. Sorhat I can so my % gain on Cd from down hill cost down testing mpgs show 27% FE improvement =54% improvement in drag reduction
What do you guys/gals think??

Hucho shows a different CdA/MPG relationship for Diesels compared to gasoline vehicles.I don't have his book with me.Perhaps a member can help us out on this one.
These relationships are predicated upon steady-state highway cruise mpg,not coasting or coastdowns.
Also,we have no idea what the engines BSFC is doing with the modifications,and all the relationships presume a constant BSFC,or gear-matching to achieve a constant BSFC which may not reflect reality.

aerohead 03-12-2016 02:13 PM

reduction
 
Quote:

Originally Posted by rumdog (Post 508732)
Ha me too freebeard i was making a funny face trying to decifer it.
54% geez thats a big drop in drag. My cap is a similar shape, i was guessing 1/4 to 1/3 reduction in drag, but would be happy to be wrong!

So far,I think that 20-21% drag reduction maximums have been reported for caps.

gumby79 03-12-2016 10:37 PM

Questions
 
Sorhat (so that)I can so my(find my) % gain on Cd from down hill cost down testing(turmnal velocity testing instead of) mpgs... (improvement for drag improvement value)
This part makes my head hurt.
Sorry temporary tourettes


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