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hi all,
This is my first post .
I am a student, Automobile engineering..India...
very much intrsted in CFD .... and numerical methods on a whole...
I am very new to this and i just wanted to start off....
This is my first so called analysis ..
I know there are a lot of flaws and mistakes.....mayb the whole method is wrong ..

plz comments pls.....

I tried this in Ansys 10. the model is not according to dimensions...i just created profile arbitrary....
:
velocity of air 28m/s along x-direction
velocity of air 0m/s along y-direction

Can somebody interpret the results for me..?.....if there is anything in it .. )

Hello pawanhv !
I'll try to comment your data.
First I think that the color shows pressure ?

So on the first graph, we can see a big vortex on the aft.
On the second we can see that there is a big underpressure under the car, that's pretty good for high speed corners !
But, air cooling is not so good as I saw in the third pic. Indeed, the air coming forward cannot reaches the rear wing because it is "pushed high" by the front tyres, which (I think) are statics ? So imagine if they roll !

Good job pawanhv, and please continue to post here !

sry i forgot to specify the name of results.....
1 Fluid Flow
2 Total Pressure
3 Vector Plot
4 X component Fluid velocity

Thnks Crystalix,,,

so does it also mean that in the second image, a relatively high pressure is created near the front wheels and a vacuume near the rear wheels...... ? ... and i think.....near the rear wheels a suction of air is created which shoots the fluid toward the rear?
correct me if i m wrong ..
I love being wrong coz it teaches me what is absolutely right ..

Well with CFD, you have to decide what results you are looking for..

I would look on the total pressure one.. and see how that affect the downforce..

Or you could use the fluid flow results and see how it affects the radiators, in a heat transfer setup..

You know stuff like that.

Oblique, tangentially related - but may be worth a giggle:
http://www.ensight.com/aero-concept-eng ... ation.html

Try a general search - 'Fluent race car engineering tutorials' - some such amalgamation may stimulate something to break from the herd. Revealing splendor.

Search term - 'Fluent race car tutorials' - has several interesting entries.

Try an alternate search engine. A new one I enjoy:
http://www.cuil.com/

Thanks for the reply, Carlos. But the I tried searched the terms you gave me and I couldn't found anything too useful. Could you let me know which ones are you referring to?

When the OWG presented its findings, it suggested that CFD models gave diametrically opposite results to wind tunnel models. Can anyone explain to a total green-horn how this could happen? I am also interested to find out what external/environmental models are used, where they come from, and how they are calibrated.

That's all I have are suggestion for you schumy7,how about another, look through the forum aero threads and PM the heavyweights for advice and concrete resources.

pgj wrote:When the OWG presented its findings, it suggested that CFD models gave diametrically opposite results to wind tunnel models. Can anyone explain to a total green-horn how this could happen?

I suspect naive CFD use without validation.

pgj wrote:When the OWG presented its findings, it suggested that CFD models gave diametrically opposite results to wind tunnel models. Can anyone explain to a total green-horn how this could happen? I am also interested to find out what external/environmental models are used, where they come from, and how they are calibrated.

Poorly done CFD. If you don't know what you are doing, you'll get bad results. Same for wind tunnel. Hell, they probably did both wrong!

AeroGT3 wrote:

pgj wrote:When the OWG presented its findings, it suggested that CFD models gave diametrically opposite results to wind tunnel models. Can anyone explain to a total green-horn how this could happen? I am also interested to find out what external/environmental models are used, where they come from, and how they are calibrated.

Poorly done CFD. If you don't know what you are doing, you'll get bad results. Same for wind tunnel. Hell, they probably did both wrong!

OWG suggested the former studies (done in CFD) were wrong.

While you're right you can mess with cfd, i think this time the limitation came from the wake structure CFD possibilities.

OWG works are based on utilisation of a favorable wake structure.

Ogami musashi wrote:While you're right you can mess with cfd, i think this time the limitation came from the wake structure CFD possibilities.

neither one of us has access to their CFD results, so I'll leave it at 'I disagree."

do u think that you can clean up the cfd photos for newbies or those who does not know how to read those pictures (not for me. I know how.) and by the way good job

Hi

Is it correct in saying fluent doesnt predict transition from laminar to turbulent very accurately?

Abdul