EcoModder.com

EcoModder.com (https://ecomodder.com/forum/)
-   Aerodynamics (https://ecomodder.com/forum/aerodynamics.html)
-   -   Help me evaluate CFD results (https://ecomodder.com/forum/showthread.php/help-me-evaluate-cfd-results-38038.html)

M_a_t_t 12-11-2019 12:07 AM
Help me evaluate CFD results
 
I have been playing around with a model of my car and putting it in a cfd program. The model is not that great, however it is pretty accurate (shape wise) from the center line of the car. Based on this I have been messing with the angle of the hood to windshield and the nose. I have a limited understanding of how the numbers should be interpreted and would like more opinions on the subject. Rather than posting a bunch of screen shots directly here I have inserted them in a google document.

(quick sample)
https://ecomodder.com/forum/member-m...st-current.png
https://ecomodder.com/forum/member-m...current-55.png

https://docs.google.com/document/d/1...it?usp=sharing

The program I used for modeling is Autodesk Inventor and the CFD is Autodesk Flow Design.

The wind speed is set to 10 m/s (I forgot to increase it) unless otherwise noted.

The 2d plane the pressure is mapped on is in the same spot for all screen shots.
  • The car is not sitting on the ground plane, would this effect how to interpret the front and top of the car?
  • I had two options for mapping, pressure or velocity. Is one better to look at or is it a combination of the two that makes the data interpretable?
  • Is there anything that you guys suggest I try and mock up and test?
  • The first thing I wanted to test was the simple hood height (because of visibility and simplicity), the only differences I see is a lower high pressure (on the scale) and a more localized section of low pressure where the windshield and the roof meet. Also something different is going on with the underside, not sure if its because of the adjusted scale or it somehow affected the undercarriage.

Thank you in advance,
Matt

freebeard 12-11-2019 12:32 AM
•The car is not sitting on the ground plane, would this effect how to interpret the front and top of the car?

Is the ground plane moving? Are the wheels represented?

•I had two options for mapping, pressure or velocity. Is one better to look at or is it a combination of the two that makes the data interpretable?

They interoperate, or something. There should be some algorithm to combine the results.

•Is there anything that you guys suggest I try and mock up and test?

Is this analyzing a 2D plane though the centerline of the vehicle? If so it's meaningless. The entire 3D form is necessary.

•The first thing I wanted to test was the simple hood height (because of visibility and simplicity), the only differences I see is a lower high pressure (on the scale) and a more localized section of low pressure where the windshield and the roof meet.

The only difference I see is the speed and pressure. What hood height difference is there? Once again, the 3D form is significant. A Jeep and a VW Beetle have flat windshields at a similar angle. But the Jeep's is square while the Beetle has a teardrop that has been truncated at the front. It's body is widest at the C-pillar.


edit:
I looked around a bit. You may find answers at www.cfd-online.com/Forums/autodesk-simulation-cfd/

M_a_t_t 12-11-2019 01:39 AM
Quote:
Originally Posted by freebeard (Post 613158)
Is the ground plane moving? Are the wheels represented?


They interoperate, or something. There should be some algorithm to combine the results.

Is this analyzing a 2D plane though the centerline of the vehicle? If so it's meaningless. The entire 3D form is necessary.


The only difference I see is the speed and pressure. What hood height difference is there? Once again, the 3D form is significant. A Jeep and a VW Beetle have flat windshields at a similar angle. But the Jeep's is square while the Beetle has a teardrop that has been truncated at the front. It's body is widest at the C-pillar.


edit:
I looked around a bit. You may find answers at www.cfd-online.com/Forums/autodesk-simulation-cfd/
1.Ground plane is stationary as well as the wheels. Same as in a wind tunnel.

1.5 Would that algorithm be the cD number or similar?

2. Can you expand on that? Other threads look at 2d profiles, which would be basically the same as a smoke overlay (like in the first post of the wind tunnel thread) and we still can make assumptions based on that data such as how small the vortex at the back of the car is. I just want to try and figure out how much difference it makes and have a plan before trying to make something on the car.
https://ecomodder.com/forum/showthre...ead-26678.html

3. Its relatively small. Like 3-4 inches up the windshield. I only put it in the center of the model because thats where the plane is. Jeep and beetles have different approaches though. Jeeps hoods are pretty much parallel to the ground. Ignoring the part at the base of the windshield the beetles is more obtuse.

I will check that out, thanks.


Wind speed set to 25 m/s. velocity instead of pressure.
https://ecomodder.com/forum/member-m...nes-tracer.png

Wind speed at 25 m/s velocity instead of pressure. It also seems like flow stays attached longer at the back.
https://ecomodder.com/forum/member-m...ght-tracer.png

freebeard 12-11-2019 02:34 AM
It appears you have a 3D shape that's being analyzed in a single plane. Do you have an isometric view? The single plane reduces the computation needed. How long does it take to generate a single view?

Further into the Wind Tunnel and Smoke thread:
http://theansweris27.com/wp-content/...02-768x466.png
Permalink #817

IIRC aerohead found a blister on the hood had no appreciable effect on his T-100 pickup.

teoman 12-11-2019 10:20 AM
From memory the software is not that slow. And it does it in 3d.

It is sometimes less confusing to view it in 2d.

aerohead 12-11-2019 10:56 AM
CFD model
 
I have low confidence in all desktop CFD simulations.Optimization of shape involves details which can only be evaluated in 3-D,in ground contact,at 'full-scale,' above critical Reynolds number,on software we can't afford,running on a supercomputer we also can't afford.
From your model,the nose is okay.The nose slope would be at saturation )no additional steeper angle would affect drag),and the windshield angle would also be near saturation.So far so good!
The aft-body ought to follow the 'template.'The last portion of your roof-line cannot support attached flow. The diffuser angle should be relaxed down to 2.8-4.0 degrees otherwise the flow won't follow that either.
The VW XL1 would be a good example to follow.It's dead-nuts on as far as shape goes.

M_a_t_t 12-11-2019 01:09 PM
Quote:
Originally Posted by freebeard (Post 613162)
It appears you have a 3D shape that's being analyzed in a single plane. Do you have an isometric view? The single plane reduces the computation needed. How long does it take to generate a single view?

Further into the Wind Tunnel and Smoke thread:
Permalink #817[/URL]

IIRC aerohead found a blister on the hood had no appreciable effect on his T-100 pickup.
Its not technically an isometric because of the angle, but there is a different view in the google doc.

a single view in the CFD is fairly quick. less than a minute for the 2d plane. About 45 seconds for the 3d and then time to settle down I guess.

The reason I am avoiding a 3d evaluation is because my model is lacking. I created it based on pictures of the car (from a distance zoomed in), but I don't have one from above to get the taper of the tail and such. I can post one if you think it would provide more information.

I wanted to test the hood to windshield because the air appeared to be separating at the back of the roof. I was hoping that it would indirectly keep flow more attached at the back by changing how it transitioned from the front roofline.

Current car @ 25 m/s
https://ecomodder.com/forum/member-m...ero-tracer.png

After letting it sit and run it changed to this:
https://ecomodder.com/forum/member-m...o-tracer-2.png

The red box is where the flow lines are originating from.
https://ecomodder.com/forum/member-m...o-tracer-3.png




Quote:
Originally Posted by aerohead (Post 613174)
I have low confidence in all desktop CFD simulations.Optimization of shape involves details which can only be evaluated in 3-D,in ground contact,at 'full-scale,' above critical Reynolds number,on software we can't afford,running on a supercomputer we also can't afford.
From your model,the nose is okay.The nose slope would be at saturation )no additional steeper angle would affect drag),and the windshield angle would also be near saturation.So far so good!
The aft-body ought to follow the 'template.'The last portion of your roof-line cannot support attached flow. The diffuser angle should be relaxed down to 2.8-4.0 degrees otherwise the flow won't follow that either.
The VW XL1 would be a good example to follow.It's dead-nuts on as far as shape goes.
Do you mean the addition to the car or the stock bumper as modeled in my last post?

At the very end where it takes a sharp turn or where the roof ends and meets the tail?

I had to compromise on the bottom of the car.

Do you think the CFD can be used as a data point? Not necessarily accurate for numbers, but just the flow pattern around the car.

aerohead 12-11-2019 02:08 PM
CFD
 
Quote:
Originally Posted by M_a_t_t (Post 613188)
Its not technically an isometric because of the angle, but there is a different view in the google doc.

a single view in the CFD is fairly quick. less than a minute for the 2d plane. About 45 seconds for the 3d and then time to settle down I guess.

The reason I am avoiding a 3d evaluation is because my model is lacking. I created it based on pictures of the car (from a distance zoomed in), but I don't have one from above to get the taper of the tail and such. I can post one if you think it would provide more information.

I wanted to test the hood to windshield because the air appeared to be separating at the back of the roof. I was hoping that it would indirectly keep flow more attached at the back by changing how it transitioned from the front roofline.

Current car @ 25 m/s
https://ecomodder.com/forum/member-m...ero-tracer.png

After letting it sit and run it changed to this:
https://ecomodder.com/forum/member-m...o-tracer-2.png

The red box is where the flow lines are originating from.
https://ecomodder.com/forum/member-m...o-tracer-3.png






Do you mean the addition to the car or the stock bumper as modeled in my last post?

At the very end where it takes a sharp turn or where the roof ends and meets the tail?

I had to compromise on the bottom of the car.

Do you think the CFD can be used as a data point? Not necessarily accurate for numbers, but just the flow pattern around the car.
Looking at the representation,I don't believe it's worth working with it.In orthogonal view,the model is failing to represent flow separation and vorticity from the square edges which would be present in the real world.I don't have any faith that it could properly represent any aspect of flow.It could lead you down a rabbit hole if you relied on it.
The bumper would be okay if it had adequate corner radii,but as depicted in plan-view,it has none at all,and guaranteed separation.Front fenders Dittoo.A-pillars ditto.
Nothing you can do at the front can solve the issue you have at the back.The present roofline is too aggressive towards the tail,and will absolutely trigger separation.No where can you exceed 23-degrees downslope.
I understand the diffuser issue,although there's no reason an active diffuser,which could deploy downwards on the highway wouldn't solve the issue.GM did it with their 'Epcot' concept of the early 1980s.
I think you'd be better off just looking at the wind tunnel flow images of real cars here on the Aero Forum.
I'm okay with CFD,just not the 'toy' kind.If you want to get serious,you better bee a millionaire!

freebeard 12-11-2019 04:34 PM
Do with this what you will: The Ford 3D Store

M_a_t_t 12-11-2019 07:39 PM
Quote:
Originally Posted by aerohead (Post 613192)
Looking at the representation,I don't believe it's worth working with it.In orthogonal view,the model is failing to represent flow separation and vorticity from the square edges which would be present in the real world.I don't have any faith that it could properly represent any aspect of flow.It could lead you down a rabbit hole if you relied on it.
The bumper would be okay if it had adequate corner radii,but as depicted in plan-view,it has none at all,and guaranteed separation.Front fenders Dittoo.A-pillars ditto.
Nothing you can do at the front can solve the issue you have at the back.

The present roofline is too aggressive towards the tail,and will absolutely trigger separation.No where can you exceed 23-degrees downslope.
I understand the diffuser issue,although there's no reason an active diffuser,which could deploy downwards on the highway wouldn't solve the issue.GM did it with their 'Epcot' concept of the early 1980s.
I think you'd be better off just looking at the wind tunnel flow images of real cars here on the Aero Forum.
I'm okay with CFD,just not the 'toy' kind.If you want to get serious,you better bee a millionaire!
I can't find the diagram I remember seeing, but I was hoping to try and get the airflow to be re-directed away from the roof at the windshield and have it come back down and reattach following the roofline. Similar to what seemed to happen with the hood to windshield model (post #3).

Are you eyeballing the slopes or calculating? I have been eyeballing. When I overlay the template (I understand has limitations) the tail pretty closely matches the upper shape. I would like to do some tuft testing, but don't really have the stuff required to record it.

https://ecomodder.com/forum/member-m...er-overlay.png


Quote:
Originally Posted by freebeard (Post 613201)
Do with this what you will: The Ford 3D Store
Thanks for finding that. They don't have the correct year escort though :(




Do you think a gurney flap at the tip of the tail would help flow? I remembered I have 2 wide angle dash cams I might be able to use to record from a chase vehicle. I will try to get something this weekend.

aerohead 12-14-2019 12:23 PM
eyeballing or..................
 
Quote:
Originally Posted by M_a_t_t (Post 613207)
I can't find the diagram I remember seeing, but I was hoping to try and get the airflow to be re-directed away from the roof at the windshield and have it come back down and reattach following the roofline. Similar to what seemed to happen with the hood to windshield model (post #3).

Are you eyeballing the slopes or calculating? I have been eyeballing. When I overlay the template (I understand has limitations) the tail pretty closely matches the upper shape. I would like to do some tuft testing, but don't really have the stuff required to record it.

https://ecomodder.com/forum/member-m...er-overlay.png




Thanks for finding that. They don't have the correct year escort though :(




Do you think a gurney flap at the tip of the tail would help flow? I remembered I have 2 wide angle dash cams I might be able to use to record from a chase vehicle. I will try to get something this weekend.
In Wolf Hucho\'s \'Aerodynamics of Road Vehicles,he presents empirical results of aerodynamic testing,dating back to 1922.
He dedicates an entire section to forebody design,drawing on Jaray,Fachsenfeld,Kamm,Waters,Pawlowski,Carr,Ahmed ,Hoerner,Emmelmann,Janssen,and Hucho.
From the visual schematics,I can just look at your rendering,and know that you\'re already at saturation.There\'ll be no problem with attached flow over the roof peak and onto the rear slope.
The important part is the slope/contour back there.That\'s where your streamlining potential is.The \'template\' contour is derived from the lowest-drag half-streamline-body of revolution.My model which used it,measured Cd 0.12 just as predicted.You\'ll never find a shape with lower drag potential.That\'s why I shared it.

M_a_t_t 12-14-2019 01:43 PM
I appreciate the advice from you guys.

Can you expand on what you mean by saturation?

Are you saying the profile is as good as its going to get and I won\'t see much improvement modifying the boat tail anymore? Therefore, I need to focus on the rest of the car.

Also, I finished the bottom section of the boat tail I just hadn\'t when I took that picture.

https://ecomodder.com/forum/member-m...214-133908.jpg

Edit: Assuming I am correct in what you mean by saturation I think I have some useful information. On a particular road in town that was recently repaved and has a 55 mph speed limit the tail makes absolutely no noise. If there was a lot of turbulence the unsupported sections would flap around right? The road is decently protected from crosswinds on both sides by trees and buildings.

freebeard 12-14-2019 02:47 PM
Thanks for posting that. Just yesterday in another thread I was lamenting the fact we haven't seen a full boat tail (on a Metro) lately.

Do you have construction pics? That show the internal structure (if any?). What do you do about tail light and the license plate?

I'd be curious what it is like living with it. Parking and & etc.

Quote:
Are you saying the profile is as good as its going to get and I won't see much improvement modifying the boat tail anymore? Therefore, I need to focus on the rest of the car.
Get some test results (coast-down or whatever) before other mods. To isolate the gain from that one modification.

As for 'as good as its going to get', consider truncating it less than a foot. See the Peter Brock Cobra Coupe or Dave Cloud's Dolphin.
http://img.photobucket.com/albums/v7...phin/DD006.jpg
https://ecomodder.com/forum/showthre...tml#post559726

aerohead 12-14-2019 03:33 PM
saturation
 
Quote:
Originally Posted by M_a_t_t (Post 613323)
I appreciate the advice from you guys.

Can you expand on what you mean by saturation?

Are you saying the profile is as good as its going to get and I won't see much improvement modifying the boat tail anymore? Therefore, I need to focus on the rest of the car.

Also, I finished the bottom section of the boat tail I just hadn't when I took that picture.

https://ecomodder.com/forum/member-m...214-133908.jpg

Edit: Assuming I am correct in what you mean by saturation I think I have some useful information. On a particular road in town that was recently repaved and has a 55 mph speed limit the tail makes absolutely no noise. If there was a lot of turbulence the unsupported sections would flap around right? The road is decently protected from crosswinds on both sides by trees and buildings.
At a certain point of increased radius or angle,no additional rounding,or steepening will produce any further drag reduction.You've hit 'saturation.'
The tail looks delicious! Thanks for doing that!:D

M_a_t_t 12-14-2019 04:43 PM
Quote:
Originally Posted by freebeard (Post 613329)
Do you have construction pics? That show the internal structure (if any?).
It's pretty simply put together. Framed it with 1" by 1/8 flat stock and covered using a roll of roof flashing. Sheet metal screws for attachment and tape to seal it up. I overlayed the template on the car and imported it into CAD. From there I plotted points along the curve and used the back of the trunk as a scale in CAD. I started with putting a loop horizontally on the car. I leveled it using cardboard and jackstands. Once that was together I started on the profile shape. There are 2 pieces that I attached to the bumper. The bottom shape I just kind of eyeballed. To get the metal above to bend I just welded the vertical parts to the cross piece and while it was hot I bent it around so that It would hit the roof. I did have to weld an extra 3 ft or so to actually reach the roof. After that I skinned it in the aluminum flashing.You can kind of see it in this picture. I can get a picture from inside later.
https://ecomodder.com/forum/member-m...027-205746.jpg

What do you do about tail light and the license plate?
The tail light is a trailer light, one of the narrow ones. It's like 1" by maybe 8 or 10 inches. The turn signals I chose initially are terrible. I bought some 4" flush mount trailer lights I have to put them in yet. I don't have a hole saw big enough. For the license plate I put 2 bolts in the sheet metal and then I put the license plate on and sandwiched it between the 2 nuts.

I'd be curious what it is like living with it. Parking and & etc.
It's not bad. Rear visibility is terrible without the side view mirrors. Right now I have the passenger side off and I don't like it. Parking isn't really a problem other than not being able to see behind you very well. Its just about the same length as my mom's 01 Pontiac Grand Prix. I usually park where there is a curb with grass overhang (I'm not sure what you call them). This way I just back over the curb and its not an issue.


Get some test results (coast-down or whatever) before other mods. To isolate the gain from that one modification.
I did a run using the instructables coast down method and excel sheet and got a Cd of .30 (vs stock .34, not verified just googled. I also had the passenger mirror off and didn't try to adjust the frontal area.) and Crr of .01285 I think one of my tires was a little low when testing though so it might be a little better than the data I got

As for 'as good as its going to get', consider truncating it less than a foot. See the Peter Brock Cobra Coupe or Dave Cloud's Dolphin.
Are you suggesting trying to follow template better and eith run a clear panel or just leave it truncated?
Quote:
Originally Posted by aerohead (Post 613334)
You've hit 'saturation.'
The tail looks delicious! Thanks for doing that!:D
Thank you, pretty much everyone has said positive things about it, including "normies".

aerohead 12-14-2019 04:48 PM
4% @ 70
 
Quote:
Originally Posted by M_a_t_t (Post 613337)
Thank you, pretty much everyone has said positive things about it, including "normies".
I believe that at 70-mph,a 10% reduction in Cd produces a 6% increase in mpg.I apologize if I screwed that up.:o

teoman 12-14-2019 06:00 PM
Quote:
Originally Posted by M_a_t_t (Post 613323)
I appreciate the advice from you guys.

Can you expand on what you mean by saturation?

Are you saying the profile is as good as its going to get and I won't see much improvement modifying the boat tail anymore? Therefore, I need to focus on the rest of the car.

Also, I finished the bottom section of the boat tail I just hadn't when I took that picture.

https://ecomodder.com/forum/member-m...214-133908.jpg

Edit: Assuming I am correct in what you mean by saturation I think I have some useful information. On a particular road in town that was recently repaved and has a 55 mph speed limit the tail makes absolutely no noise. If there was a lot of turbulence the unsupported sections would flap around right? The road is decently protected from crosswinds on both sides by trees and buildings.

Holy moly!

They let you ride around in that? Gotta love the USA.

freebeard 12-14-2019 06:55 PM
Quote:
Quote:
The tail looks delicious! Thanks for doing that!
Thank you, pretty much everyone has said positive things about it, including "normies".
Don't underestimate the significance of aerhead's approval. :thumbup:

0.34=>0.30 sounds about right. Now go after the wheelwells.
Quote:
They let you ride around in that? Gotta love the USA.
"Hells yeah — 'Murica!" :)

The result may vary by jurisdiction.

teoman 12-14-2019 07:01 PM
Check out the software that freebeard linked a couple of months back. Appears to be slightly more capable that the Autodesk stuff.

freebeard 12-14-2019 10:11 PM
Permalink #4 was just for purposes of illustration.

The key to low-compute-power CFD IMHO is OpenVDB:
Quote:
Originally Posted by DDG
OpenVDB
[Search domain www.openvdb.org] https://www.openvdb.org
OpenVDB is an Academy Award-winning open-source C++ library comprising a novel hierarchical data structure and a suite of tools for the efficient storage and manipulation of sparse volumetric data discretized on three-dimensional grids.
OpenVDB - Download

[Search domain www.openvdb.org/download/] https://www.openvdb.org/download/
OpenVDB includes a small number of Maya nodes, primarily for conversion of geometry to and from OpenVDB volumes and for visualization of volumes. This archive contains several example scene files that demonstrate how to use the nodes. Maya Examples zip - Aug 8 2016

OpenVDB - Wikipedia
[Search domain en.wikipedia.org/wiki/OpenVDB] https://en.wikipedia.org/wiki/OpenVDB
OpenVDB is an open source C++ software library comprising a novel hierarchical data structure and a large suite of tools for the efficient storage and manipulation of sparse volumetric data discretized on three-dimensional grids.
It's all about the sparse inverted B-trees, if ya know what I mean. And being able to attach arbitrary attributes to each voxel. If you need it, the odor of hickory smoke. :)
https://i.ytimg.com/vi/R8Y9VqU_YTI/maxresdefault.jpg
https://i.ytimg.com/vi/R8Y9VqU_YTI/maxresdefault.jpg
Instead of computing every voxel in the virtual wind tunnel, it looks more diligently closer to the aeroform.

It's above my pay grade. :(

M_a_t_t 12-14-2019 11:54 PM
Quote:
Originally Posted by aerohead (Post 613338)
I believe that at 70-mph,a 10% reduction in Cd produces a 6% increase in mpg.I apologize if I screwed that up.:o
Fixed :thumbup:

Quote:
Originally Posted by teoman (Post 613345)
Check out the software that freebeard linked a couple of months back. Appears to be slightly more capable that the Autodesk stuff.
Quote:
Originally Posted by freebeard (Post 613352)
The key to low-compute-power CFD IMHO is OpenVDB:

It's all about the sparse inverted B-trees, if ya know what I mean. And being able to attach arbitrary attributes to each voxel. If you need it, the odor of hickory smoke. :)
Instead of computing every voxel in the virtual wind tunnel, it looks more diligently closer to the aeroform.

It's above my pay grade. :(
I'm not sure I am following on that. Is this a modelling and CFD or? Open source is usually free right?

Quote:
Originally Posted by teoman (Post 613342)
Holy moly!

They let you ride around in that? Gotta love the USA.
I've had 2 cops follow me (both from a small town on seperate occasions) neither one pulled me over. I did research regarding it and aside from small stuff (no reflectors in the rear sides) it is legal. There isn't any inspection here, but the bumper and other crash related stuff is still there it's just covered up.

freebeard 12-15-2019 01:43 AM
You've added a crumple zone. Worst case and heaven forfend, but if you're rear-ended the fool behind you will be safer. :thumbup:

You should strongly consider the old thread from 2013, Military theme for fun ...and function

Bumblebee stripes and some cryptic Zombie Response Vehicle markings would not be out of place.

Quote:
I'm not sure I am following on that. Is this a modelling and CFD or? Open source is usually free right?
Well.... It's a deep subject. :)

That kind of work involves a tool-chain. OpenVDB is a visual database. It can be queried by anything that can structure a query. It's currently employed by the movie industry, Maya and (apparently*) Blender.

I took a deep dive into the [pseudo]code structure a few years back. I recognized a lot of it from when I was trained to edit Mac OS HFS structures (I worked for Symantec for 9 years). B-trees allow you to get to any point in the point cloud in a discrete number of steps. Shallow trees have fewer steps to get to an arbitrary point.

There was a brilliant way of encoding things like pressure or a motion vector for each point but I don't recall and prolly couldn't explain if I did.

So there's that. I'm like a scarecrow in a field pointing thataway.


*I struggle with Blender itself, let alone where the API for the C++ libraries are. Have you looked at Blender? I'm not doing any render farming on my laptop.

aerohead 12-18-2019 11:03 AM
Gurney flap
 
So far,no really low drag car has used a Gurney flap as a palliative for flow separation.Hucho and the others,who've explored really minimum drag all recommend that we stay on the streamlined contour,then if length is an issue,just chop the body as Koenig-Kamm did at the FKFS,next door to Daimler-Benz.

freebeard 12-18-2019 01:25 PM
The Gurney flap aka wickerbill was a field expedient. As was the Gurney Bubble.

https://www.gt40s.com/media/mkiv-gur...l?d=1532040050
https://www.gt40s.com/media/mkiv-gurney-bubble.901/

freebeard 03-04-2020 05:54 PM
I came across something and this thread seems most relevant:

https://www.youtube.com/watch?v=N4YMYGDEcPM
This speaks to the integration of OpenVDB with Blender. It is about importing data sets into the program, where for CFD the internal physics engine would be used to generate the data.

But it shows that the future isn't quite here yet.


All times are GMT -4. The time now is 03:20 PM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com