Aerodynamic design AND optimization of an f1 rear spoiler

[Zweeper]

okay, another question, a very "silly" question maybe, but just to get sure ^^

when i use the wortman FX 63-137, i have to flip the profile horizontally like seen here:

http://img253.imageshack.us/img253/2509/fx63137.jpg



i already have all the coordinate points for this profile, but is there a fast way to change all coordinates that the profile is flipped? I want to import the points later with gambit.


Greetings!

[flynfrog]

you could do it in excel with your point table just mutiply your points on the axis you want to flip. You could simulate it upside down your CFD doesnt care.

also you might want to add some camber to it.

[kilcoo316]

i already have all the coordinate points for this profile, but is there a fast way to change all coordinates that the profile is flipped? I want to import the points later with gambit.

C'mon dude.


Your training to be an engineer. A simple geometric manipulation like that needs to be bread and butter!


As flynfrog says, excel will do the flips very easily.


Personally, what I've done is used MATLAB to general a full journal file of the points for reading into GAMBIT, so the whole geometry is there ready to go.

[PlatinumZealot]

Gambit is A part of ANSYS right? I need to get that program!

[Zweeper]

i already have all the coordinate points for this profile, but is there a fast way to change all coordinates that the profile is flipped? I want to import the points later with gambit.

C'mon dude.


Your training to be an engineer. A simple geometric manipulation like that needs to be bread and butter!


As flynfrog says, excel will do the flips very easily.


Personally, what I've done is used MATLAB to general a full journal file of the points for reading into GAMBIT, so the whole geometry is there ready to go.

yes don't worry, i already solved the problem
the easier way was to flip the whole wing with pro engineer (i use pro-e to create the wing) and import it then into gambit.

[Zweeper]

But i have another question for the moment.
The nowadays used rear wings are all multi-element wings, is there a good web page or book which explains exactly WHY these wings use multi-element wings?

I need some standards for all of these multi-elements and also some ideas for the Angle of Attacks.


Greetings

[flynfrog]

p competition car aerodynamics by McBeath

[Mystery Steve]

.
The nowadays used rear wings are all multi-element wings, is there a good web page or book which explains exactly WHY these wings use multi-element wings?

It's simple. Take a wing at zero angle of attack and start to increase the angle of attack and you'll get a greater lift coefficient. At some point you start getting separation on the low pressure side and the wing stalls. If you were to look at all the elements together, it would look like a high-camber wing profile, which is good for downforce but has separation problems at relatively low angles of attack. Using multi-element wings is similar to using slats/flaps on an aircraft that separate from the wing. As the angle of attack increases with the multi-element wing, some of the air flows between the elements from the high pressure side to the low pressure side of the wing filling in the separation. So you get the high coefficient of lift from the higher angle of attack without the stall from flow separation.

EDIT: Just realized I'd already posted more or less the same information on page 2 of this thread. Check out that video I posted again and it does kind of show it, although not very well. Another thing to consider with the separation is the upwash effect of an inverted wing, that is the upward velocity imposed on the air as it goes past a wing. Notice in the video that the upper wing is a multi-element wing, and there is a lower single-element wing. If you design correctly, you can also use the upwash from the lower wing to help "fill" the separation to an extent and increase the camber or angle of attack of the upper multi-element wing.

[Mystery Steve]

If you haven't already... check out "Race Car Aerodynamics" by Joseph Katz. I haven't personally read McBeath's book so I can't speak to it, but I do know that Katz's book is well written and covers multi-element wings. At any rate, it doesn't hurt to read multiple sources. You may also want to do a theses/dissertation search. You can probably find some people who have done case studies on this topic if you search hard enough, at least in the aeronautical field. Not sure what you'll find published in the automotive field, but sae.org might have some white papers on this stuff.

And for the sake of those reading this thread who may not be technically minded and don't know what we're talking about with separation/stall, this video is good pictorial (and is an excuse to post colorful pictures):

[youtube]http://www.youtube.com/watch?v=Ti5zUD08 ... r_embedded[/youtube]

[SZ]

The nowadays used rear wings are all multi-element wings, is there a good web page or book which explains exactly WHY these wings use multi-element wings?

Seriously?

Stop with the CFD and go through the theory. Hit up some PDF search engines, there are complete lecture note series available. Some universities even make their course notes available online. Try here.

Do the research, and you'll find this much easier.

[kilcoo316]

Gambit is A part of ANSYS right? I need to get that program!

No.

You really don't want to get gambit.


What you want is ICEM.

[kilcoo316]

The nowadays used rear wings are all multi-element wings, is there a good web page or book which explains exactly WHY these wings use multi-element wings?

Seriously?

Stop with the CFD and go through the theory. Hit up some PDF search engines, there are complete lecture note series available. Some universities even make their course notes available online. Try here.

Do the research, and you'll find this much easier.

+1


Absolutely no point jumping into CFD if you don't have the slightest notion about how to interpret the results.

Even less point in jumping into CFD if you don't have a basic grasp of aerodynamics.

[xxChrisxx]

In Zweeper's defense I know just how much of a pain projects are at Universities. They really throw you in at the deepend, they don't tell you what you should know prior to the start of a project, if they've never covered multi element wings before how should he know. To behonest i'd be surprised if they've given any extensive CFD traiing at all, thats another... suck it and see.

It was like that for my Uni project.

At least he asked the right thing, us to point him to a book. Not just tell him.

[flynfrog]

I would start with 2d simulation first to cut down on time. get your airfoils and your AoA right then move to three dimensions and work on endplates after that add a gurney if you are feeling frisky.

this will proably teach you the most.

You might look and see if you have a FSAE team on campus develop a wing for there car maybe do a front and rear. That way you have real world speeds and Hp to deal with.

[SZ]

In Zweeper's defense I know just how much of a pain projects are at Universities. They really throw you in at the deepend, they don't tell you what you should know prior to the start of a project, if they've never covered multi element wings before how should he know. To behonest i'd be surprised if they've given any extensive CFD traiing at all, thats another... suck it and see.

True.

Though I hate watching forums turn from a place for people to discuss knowledge to one where individuals demand answers. Not the same thing.

At least he asked the right thing, us to point him to a book. Not just tell him.

It's far from the worst request I've seen, though a keen student would have done a quick search themselves first... assuming Zweepers' university doesn't have a library, or that his aeronautical coursework doesn't, at some point, have a recommended text with wing theory in it.

get your airfoils and your AoA right then move to three dimensions and work on endplates after that add a gurney if you are feeling frisky

Why?

You might look and see if you have a FSAE team on campus develop a wing for there car maybe do a front and rear. That way you have real world speeds and Hp to deal with.

Or you might look into the third post of this thread - which was very, very valid - then look into a library, then think for a bit. And achieve a lot.