r/aerodynamics

Has anyone here seen a genuinely high-resolution study of the earliest-time acceleration regime for objects moving vertically through fluids before substantial drag closure develops?

I’m interested in controlled comparisons using:

* identical density ratios,

* identical masses,

* but different geometries (sphere vs cylinder vs hemispherical-ended capsule),

* and ideally different surrounding media adjusted to equivalent densities.

The reason I ask is that most literature and demonstrations focus heavily on terminal behaviour, while the initial acceleration window seems comparatively underexplored experimentally despite being potentially important for separating:

* density contrast effects,

* added-mass coupling,

* geometry-dependent participation,

* and later drag evolution.

Would appreciate pointers to papers, datasets, or experimental groups working on this type of problem please.

Thankyou.

I am doing an aerodynamics project for one of my classes, where I am trying to make a race car better aerodynamically. i am working with a Corvette Z06 GT3, and i have made these changes. Baseline Test

Car Model:
Corvette C8R GT3
File:
CorvetteC8R-TFSport.stl 
Speed:
85.9 Mps
Drag:
4,925 N
Lift:
-8,790 N
Weight of car:
12,209 N
Improvement to the last variation:
N/A
Notes:
OG model did not have a s duct, so I added that.

V1:

Car Model:
Stalion V1
File:
stalionv1.obj
Speed:
85.9 Mps
Drag:
4,784
Lift:
-6,458
Weight of the car:
12,209 N
Improvement to the last variation:
~200 N less drag
~2,000 N less Downforce
Notes:
When making the s duct for baseline, there were 2 random pockets next to the s duct inlit, which caused a lot of drag, so I removed them. I added wheel covers to all wheels, I added basic side skirts, closed the bottom of the front wheel wells to some extent, and added some small, rudimentary bargboards in front of the rear tires.

V2:

Car Model:
Corvette C8R GT3 V3
File:
StallionV2.obj
Speed:
85.9 Mps
Drag:
4,677 N
Lift:
-8,561 N
Weight:
12,209 N
Improvement to the last variation:
~100 N less Drag
~2,000 N More Downforce
Notes:
Made the covers for the nostril things more sloped, to more easily flow air into the s duct. Added Mini barge boards to the front tyres. Made the barge board for the rear tires lead more to the diffuser, added a mini double diffuser, and added door winglets.

V 3.6
Car Model:
Corvette EW GTX V 1.5
File:
Educated Wish.STL
Speed:
85.9 Mps
Drag:
4,271 N
Lift:
-5,770 N
Weight:
12,209 N
Improvement from the last iteration:
~400 N less drag
~3000 N Less Downforce
Notes:
After the chaos of V3, I reverted to an earlier model, gonna work on DAI later.
Added endplates to the rear wing, top, and bottom. Added ‘x-wings’ to the side of the engine cover. The main goal of this version is to shrink the file size. Was 124 Mb, now 11. Also, forgot to remove DAI, so I guess we are testing that too.
Post Simulation: I am making a lift in the s duct. I have no idea why.

I don't think I am understanding the s duct right. as you can see, i have lost about 1000 N of downforce, and looking at the slices, almost all of the lift is coming from hat i think is the s duct.

Edit: the missing vidios are here https://drive.google.com/file/d/1i1esaCWPnHhvHz6I5hqR4VYGsk5pTzHB/view?usp=drive_link slices

https://drive.google.com/file/d/1CGWZQvsu-5_YiBJIqtKROOdrUToHuWyf/view?usp=drive_link streamlines

I just finnished the simulation with a moving ground at 85.7 Mps. downforce is 8039 N, drag is 4773 N. vidio is here: https://drive.google.com/file/d/1VUMerv69GNTkIwbSnHZU522oipzDuaSS/view?usp=drive_link

Vertical Propulsion Design Helpp

Folks, I need help with a design. I am a novice at this so any help works. I want a Propulsion design that could lift (motor's weight + circuit) to a metre height. I need suggestions for most optimum Propulsion designs since I don't know jacksh- about aerodynamic systems. So please help me.

Hi everyone!

Some of you are working in motorsport so I'm sure this will help you at least a little bit.

Over the last few months I built a web app for motorsport wing design which lets you download and simulate your projects. It has:

• Built-in airfoil library (but you can also import a custom airfoil shape)
• Parametric setup (chord, span, AoA, endplates)
• Multi-element wing designer (up to 3 elements) - gap/overlap setup
• Modifiers (Curvature & Variable AoA - different AoA on the wing tips vs its core)
• Export 3D files in .STEP & .STL format (for free)
• Possibility to save your projects and airfoil profiles for further work

There's also a simulation tool based on XFOIL - that outputs crucial information on your design (CL, CD, L/D, stall margin). Additionally, it gives a proper PDF report with more in-depth analysis (Cp distribution, Pressure vectors, Transition location, Boundary-layer health & Separation bubbles). It's not for free since it consumes a bit of CPU but everyone gets free tokens to try it out. All the other features remain FREE.

It started as something I made for my own use. Figured it might save someone else a few hours too. Feedback welcome - especially from anyone actively doing aero work.

You can try it out here: https://www.aerodesignstudio.com/

If you have trouble using these features, you can watch this video which covers what's new and how to use it - https://www.youtube.com/watch?v=ZxLITPJSy78

https://preview.redd.it/jjhyr0obi30h1.png?width=3840&format=png&auto=webp&s=a592b97c6f5d8bfadc0b9d9d579f854ff69baa9a

https://preview.redd.it/28lxhu2ai30h1.png?width=3840&format=png&auto=webp&s=05ead9908bb062b1a3d4e02cf8d6a09678c64008

Unsure if this is the correct subreddit. I do not have working a/c, but I do have one window (in my room) and two box fans. I want my room as cool as possible. What would be the best setup? Should I put the fan in the window facing inward or outward (or neither); should the other fan be by the adjacent or opposite wall; should the door be open or closed; and does it matter if I’m trying to cool the room down or get rid of a smell?

So I have a Chrysler 300, something like this:

https://preview.redd.it/hhokcz2y2hzg1.jpg?width=693&format=pjpg&auto=webp&s=46984348b2b28007360d168dcef9952dff812c95

And one of these little Harbor Freight trailers, minus the spare tire.

https://preview.redd.it/3bhj7p9n3hzg1.jpg?width=994&format=pjpg&auto=webp&s=9eb20ed44710203068f183243174213e903df695

So together they're like this, sorry no pic handy without the wood on it.

https://preview.redd.it/j95vdmt85hzg1.jpg?width=753&format=pjpg&auto=webp&s=1f8cb65b16f41e4cdac84df2c5590020d98adcfb

Anyway, to the question.

It really feels to me like the car is faster on the highway when pulling the empty trailer. Like it moves at speed more effortlessly, that it takes less throttle to maintain speed. Like the trailer is smoothing out the air behind the car, reducing turbulence and thus overall reducing drag despite the fact that the trailer has drag of it's own.

I haven't had a chance to do real testing to see if pulling the empty trailer improves MPG, it feels like it might. Though I might do it tomorrow.

Does this make sense and if so, what does it tell me about the aerodynamics of my car?

I'm currently finishing 8th grade and moving into 9th grade. I want to study aerodynamic design for transport aircraft. Could you recommend any technical literature on this topic? And maybe becould give some general advice me on this. Maybe there are some people here who are doing this and I could talk to them, idk.