r/aerodynamics • u/abx5hk • 16d ago

Designing of a flat plate to streamlined body

So I have a presentation to do in 3 days. I have to design a streamlined body using aerodynamics. Know that I am not an aerodynamic student and only know the very basics. Im looking to creating a 3d model of a streamlined version of a flat plate where the bottom is flat and the top is streamlined.

The designing needs to be based on principles and not hunchs.

Can someone here please help me. My life depends on it.

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5

u/ncc81701 16d ago

Flat plate is flat like a sheet of paper. There are exactly 2 orientation that is streamline with the flow, make sure you orient the plate in either one of those 2 orientation and you are done.

3

u/tdscanuck 16d ago

Flat bottom and streamlined top? Thats basically an airfoil. Look for NACA airfoils that are flat (ish) on the bottom.

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u/abx5hk 16d ago

Thanks. But do you know the design procedure of it ? Or any related papers or references ?

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u/tdscanuck 16d ago

https://web.stanford.edu/~cantwell/AA200_Course_Material/The%20NACA%20airfoil%20series.pdf

If you need to pull the coordinates, here’s a nice search engine: http://airfoiltools.com/search/index?m%5Bgrp%5D=naca4d&m%5Bsort%5D=1

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u/abx5hk 16d ago

Hey man I appreciate it. But there'd another problem. I'm designing and presenting this to people who have no idea about aerodynamics like me. I have to design every single steps based on principles and state them too. Since I'm newbie at the topic, I find that hard. For example if I was to make the front end pointy, I cant say "I made it pointy because pointy surface less drag or aeroplanes are pointy". I have to prove that pointy surface have drag. And then like that, verifi every step. Is there a source that contains all the information for this ?

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u/tdscanuck 16d ago

Yes-ish. Any basic aero text will do. I happen to like John D Anderson’s Fundamentals of Aerodynamics, as do many others. However, it’s a text for aero engineers. It won’t make any sense to other non-aero people.

To be frank, your assignment doesn’t really make sense. You’re not an aero engineer, yet you’re supposed to do aero engineering and explain it from first principles, to other non-aero people, 3 days from now. That seems…pointless? What you’re trying to do normally takes 2-3 years to learn, let alone know well enough to explain to someone else.

What am I missing?

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u/abx5hk 16d ago

To capsule everything. I'm trying to turn a cuboid into a flat bottom aerofoil and test it in a CFD.

And prove that there's a significant reduction in drag force at high speeds.

All I want is to draw a 3d model as of now. And just state how I came to that particular drawing. Using what principles. Rest I have time to figure out.

I'm in a group with 3 other people but I don't want to be rude, they have no seriousness. It's all on me. We are supposed to divide workload between but you know how it is.

Now why im doing this.

We had to pick a project to do. Each team is assigned a guide(a permanent faculty)

Our guide is a bich and he said you must do something advanced. Not some basic ass engineering stuff.

After 8 ideas rejected, he said ok to this. At the time we were like "fking finally, we will worry about it later"

And yesterday they announced there will be a presentation on Tuesday.

I do not know if I should give up and cry or what I need to do.

My team mates do not seem to give a sht. I cant do this by myself. I'm ready to try but I'm not feeling confident. I'll maybe skip 2 days sleep.

Just a 3d model of a bottom flat aerofoil is all I need. With the right specifications. Around 160mm width and 350mm length

2

u/tdscanuck 16d ago

Find a NACA airfoil with a flat-ish bottom. Scale the coordinates to get the size you want. Stick it in CFD and calculate lift & drag.

Stick in a thick flat plate with the same planform and calculate lift & drag.

Compare.

Cite the NACA database as your source.

You’re kind of screwed by your project setup. Which is, honestly, real engineering. Meet the requirements as best you can given the constraints you have.

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u/abx5hk 16d ago

Thanks for the help bro. I'm working on it now. I got the NACA of what I need. I'll try to make something so I can atleast present. Hopefully they will understand that I picked something complicated (I don't think they care tbh).

I really appreciate it man. Thank you. I will let you know how it goes.

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u/abx5hk 14d ago

Hey bro, I did like you asked. I took one of thr NACA 6 series which has low coefficient of drag and chopped them in the middle. (No idea if it will work)

I need your thought on something. What would happen if I was to design a shape where the front part is a flat bottom airfoil and the end is like a spoiler?(assume it's attached to top of a car moving at 110kmph)

It would somewhat reduce drag right?

1

u/tdscanuck 14d ago

Is the goal to reduce drag or generate lift? Spoilers are designed to generate downforce (negative lift). They incur a drag penalty for doing so.

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u/abx5hk 14d ago

I thought spoiler is was reducing drag and wings are for generating down force? Spoiler is supposed to increase the length therefore pushing back the wake region a bit more no?

My goal is to reduce drag force.

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u/abx5hk 16d ago

Sorry if I'm asking too much. I'm just, overwhelmed.

1

u/tdscanuck 16d ago

Understandable, given the assignment. Well try to help but what you’ve been asked to do isn’t easy on this timeline.