F1 In Schools help : Pudin's project

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Izzy410
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Re: F1 In Schools help : Pudin's project

Post by Izzy410 » Sun Oct 24, 2010 7:06 am

You changed the head wind speed which affects it. there's a terminal velocity where peak performance is achieved.

anyhow the proper speed is 18 m/s. to insert turbulence wind. err i get back to you. i have to do some stuff. when im free in like 5 hours i'll post how to. tyre rotation is a bit simple. double click the tyres and then click atribute. and you have to calculate by the size of your tyre, the degrees of rotation per second. and make sure its CLOCKWISE ! :)
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pudin
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Re: F1 In Schools help : Pudin's project

Post by pudin » Sun Oct 24, 2010 8:17 am

I try to change the co2 chamber a bit
It look simpler.
What do u think?

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pudin
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Re: F1 In Schools help : Pudin's project

Post by pudin » Sun Oct 24, 2010 12:22 pm

Izzy410 wrote:You changed the head wind speed which affects it. there's a terminal velocity where peak performance is achieved.

anyhow the proper speed is 18 m/s. to insert turbulence wind. err i get back to you. i have to do some stuff. when im free in like 5 hours i'll post how to. tyre rotation is a bit simple. double click the tyres and then click atribute. and you have to calculate by the size of your tyre, the degrees of rotation per second. and make sure its CLOCKWISE ! :)

Thanks mate
=D
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flynfrog
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Re: F1 In Schools help : Pudin's project

Post by flynfrog » Mon Oct 25, 2010 4:28 am

pudin wrote:I run another test today with 19 m/s wind and 500 literation

Forces
X = -2.144454E+00 m
Y = 2.498600E-01 m
Z = 1.943947E-02 m

Velocity

Cdx = 2.119967E-01
Cdy = 9.393115E-03
Cdz = 2.835454E-03


The drag became less than before.
Can someone explain this?
iterations are trys that the software takes to sole you model. It works from two sides trying to reach convergence or get really close. Think of it as trying to guess a number playing the higer lower game


Is there an option to select mesh size?

pudin
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Re: F1 In Schools help : Pudin's project

Post by pudin » Mon Oct 25, 2010 1:08 pm

flynfrog wrote:
pudin wrote:I run another test today with 19 m/s wind and 500 literation

Forces
X = -2.144454E+00 m
Y = 2.498600E-01 m
Z = 1.943947E-02 m

Velocity

Cdx = 2.119967E-01
Cdy = 9.393115E-03
Cdz = 2.835454E-03


The drag became less than before.
Can someone explain this?
iterations are trys that the software takes to sole you model. It works from two sides trying to reach convergence or get really close. Think of it as trying to guess a number playing the higer lower game


Is there an option to select mesh size?


There is mesh size,what the heck is that for?
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flynfrog
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Re: F1 In Schools help : Pudin's project

Post by flynfrog » Mon Oct 25, 2010 2:40 pm

when they CFD program works it cuts your model up into tiny chunks to calculate the fluid flow on that part of the surface. The tighter the mesh the smaller the chunks to finer the resolution. Image

pudin
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Re: F1 In Schools help : Pudin's project

Post by pudin » Tue Oct 26, 2010 10:57 am

flynfrog wrote:when they CFD program works it cuts your model up into tiny chunks to calculate the fluid flow on that part of the surface. The tighter the mesh the smaller the chunks to finer the resolution. Image

It means,more time needed to finish and more accurate reading is it?
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pudin
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Re: F1 In Schools help : Pudin's project

Post by pudin » Tue Oct 26, 2010 12:52 pm

I've made major changes to the sidepods by hollowing it.
I manufactured the car and realize that its mass above average.
Im gambling by hollowing the sidepods.
I also change the co2 nozzle to a new one to follow the regs.
i didnt have much time to test this car yet.
I combined the curved sidepods that flynn said with the hollows.
Is this better or worst?
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flynfrog
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Re: F1 In Schools help : Pudin's project

Post by flynfrog » Tue Oct 26, 2010 1:14 pm

I cant say if its better or worse. Race cars are a compromise. You now have a way to quantify the added drag (hint use your cfd) You can also tell how much weight was saved. So you can tell the energy needed to move that much mass to the end of the track and you know how much drag you can save other wise. This is where it starts to get fun :wink:

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Re: F1 In Schools help : Pudin's project

Post by flynfrog » Tue Oct 26, 2010 1:15 pm

pudin wrote:
flynfrog wrote:when they CFD program works it cuts your model up into tiny chunks to calculate the fluid flow on that part of the surface. The tighter the mesh the smaller the chunks to finer the resolution. Image

It means,more time needed to finish and more accurate reading is it?
correct

pudin
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Re: F1 In Schools help : Pudin's project

Post by pudin » Tue Oct 26, 2010 1:45 pm

flynfrog wrote:I cant say if its better or worse. Race cars are a compromise. You now have a way to quantify the added drag (hint use your cfd) You can also tell how much weight was saved. So you can tell the energy needed to move that much mass to the end of the track and you know how much drag you can save other wise. This is where it starts to get fun :wink:

Fun?!
Im getting my head tied up thinking how to make my car stay at 55 grams.
BTW,am i changing the rear secondary wing too fast?
But,it is looking pretty much elliptical shape for my whole car to me.
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flynfrog
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Re: F1 In Schools help : Pudin's project

Post by flynfrog » Tue Oct 26, 2010 2:10 pm

Over all the basic shape looks pretty good. Are you to heavy or to light?
I would still do a sharper rear tail so you are not ending in a radius.

pudin
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Re: F1 In Schools help : Pudin's project

Post by pudin » Tue Oct 26, 2010 2:48 pm

flynfrog wrote:Over all the basic shape looks pretty good. Are you to heavy or to light?
I would still do a sharper rear tail so you are not ending in a radius.
Too heavy,around 30 grams without the tyres and aerofoils

Im running the car in the CFD now,hope that it will be better.
I'll change the rear tail as soon as i finished analyse the car.
What about the secondary front wing?
Do i need the df produced by the secondary front wing or just let it be straight?
More df sure makes my car stick at the track but the penalty is drag.
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pudin
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Re: F1 In Schools help : Pudin's project

Post by pudin » Tue Oct 26, 2010 4:02 pm

These are the image of the test.
The drag was a bit lower than before than before.
Old : 0.2429
New : 0.2250

Image
There is a tyre here but i hid it,u can see that the air some escape through the top but some hit the tail and got nowhere to go and then flow through the bottom of the tail

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This is the velocity contour of the car

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There it is,some air escaped through top and side.And i realize that im changing the rear tail too fast,is it right?

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Here you can see the same shape of air circulation from the side pods.


Oh,and i forgot to upload the body contour of the sidepods.
But,they all blue in colour which means VACUUM!
Darn,should i sacrifice the mass or not?
Vacuum clearly add drag but hey they decreased not increase.
Weird
:?:
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flynfrog
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Re: F1 In Schools help : Pudin's project

Post by flynfrog » Wed Oct 27, 2010 1:51 am

you should do some more levels of flow lines to see how the flow is between your body and your co2 chamber.


to save weight maybe get rid of the inner side pods all together. make the center body as thin as possible and try to close off the under body some.


I found my old co2 car in the garage today. Not as well developed as yours. I eyeballed it and cut it out by hand. The wheels were to be enclosed but the rough track kept causing it to roll over. Its best time was completed while sliding on its top.
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