Front wing analysis - Needs interpretation

[Taylans]

Hi,

This is my first post here. I am a student from Concordia University in Montreal, Canada, and preparing a little project/report whose subject is aerodynamic analysis of front wings of f1 cars.

Although I have been reading lots of posts from this forum and the pages I found through links posted here, am still not sure what to check for on my analysis. I know that the most important issue is having higher down-forces, therefore I checked forces on upper surface and lower surface of the wing. Another method, I guess, may be checking the pressures on both surfaces. But, still not sure whether I am doing it right.

I am posting two images and a small portion of results. Any kind of critics/comments and help greatly appreciated.

http://www.tayse.com/wing

Posted images and results just for test purposes, so do not mind the primitive shapes. I am going to model a couple different wings from different teams, maybe modify them slightly then test them and compare the results.

Thanks in advance for your help,

Taylan.

[AeroGT3]

Hi,

This is my first post here. I am a student from Concordia University in Montreal, Canada, and preparing a little project/report whose subject is aerodynamic analysis of front wings of f1 cars.

Although I have been reading lots of posts from this forum and the pages I found through links posted here, am still not sure what to check for on my analysis. I know that the most important issue is having higher down-forces, therefore I checked forces on upper surface and lower surface of the wing. Another method, I guess, may be checking the pressures on both surfaces. But, still not sure whether I am doing it right.

I am posting two images and a small portion of results. Any kind of critics/comments and help greatly appreciated.

http://www.tayse.com/wing

Posted images and results just for test purposes, so do not mind the primitive shapes. I am going to model a couple different wings from different teams, maybe modify them slightly then test them and compare the results.

Thanks in advance for your help,

Taylan.

I would look for lift and drag and even moment coefficients as indicators of performance. There are also more qualitative things like whether or not it stalls - you don't want separated flow in front of the the tray inlet! What percentage of the drag is pressure and what percentage is viscous? Those are things I'd be interested in.

Maybe some Cp plots at different chord locations. A comparison of everything I mentioned with and without end plates perhaps?

It looks like you're using FloWorks? Did you do a moving ground plane or a ground plane at all? That will have a big effect. If you're doing CFD, there are a lot of things on the CFD end you need to justify as having been done correctly before your results can be taken to mean anything. What's you knowledge of CFD like?

[Taylans]

Thanks for the response Robert,

In this semester, I took a finite element analysis and a Cad/Cam class in which they teach us how to use Catia. To be honest, my CFD knowledge is somewhere between nothing and a little, but I took a fluids mechanics class before and I have been using both Ansys and Catia for three months now. I know it sounds a very short period of time, but I guess I know how to use both softwares good enough to write my report.

I am using Ansys CFX. For my report, results will not have to be really accurate, all I need is some results which are not way too different than real ones, so that I can compare different models and say which one is better.

I have another question. When I do a solution with ansys, there is huge differenece between results that I got with 2 iterations and 10 iterations? Why so?

Yes, there is a ground floor to take its effect into consideration.

I was just wondering if I can say which design is better by only looking at the pressure differences of each model after only 2-3 iterations?

[AeroGT3]

I have another question. When I do a solution with ansys, there is huge differenece between results that I got with 2 iterations and 10 iterations? Why so?

Yes, there is a ground floor to take its effect into consideration.

I was just wondering if I can say which design is better by only looking at the pressure differences of each model after only 2-3 iterations?

Everything after 2-3 iterations is absolutely rubbish! Solutions takes hundreds or thousands of iterations to converge.

In its most basic form, what CFX is doing is looking at the current flow field, and predicting what the flow field will look like a very short time in the future. In reality, it takes several seconds for the flow field to "settle down," and this can mean thousands of iterations since the timesteps CFX takes are so small.

I highly recommend you read up on the very basics of CFD and do a few tutorials if you can find them. A solution after 2-3 integrations is not a finished one!

As far as looking at the pressure contours and determining the quality of the wing - I'd say you probably aren't at that level yet. Look at lift and drag coefficients. If you have the total force over the wing in each direction, this should be easy to calculate by hand if CFX is not doing it already.