CFD of F1T Modified PERRINN F1 Car

Here are our CFD links and discussions about aerodynamics, suspension, driver safety and tyres. Please stick to F1 on this forum.
MadMatt
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Re: CFD of F1T Modified PERRINN F1 Car

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Very nice! What numbers do you get? Could the outwash of the front tyres wake be increased?

chaitali31
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Re: CFD of F1T Modified PERRINN F1 Car

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Excellent thread..!!!

ggaggio19
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Re: CFD of F1T Modified PERRINN F1 Car

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Excellent thread, really =D> =D> . I am taking this as a sort of baseline for my setup. Until now I am getting a CxS ~1.14 and CzS ~1.8 which is much less than what you are quoting. What ride height you are running the calculation at?

I am not sure why CzS is so off respect to literature... :? #-o

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jjn9128
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Re: CFD of F1T Modified PERRINN F1 Car

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ggaggio19 wrote:
Wed May 27, 2020 3:21 pm
Excellent thread, really =D> =D> . I am taking this as a sort of baseline for my setup. Until now I am getting a CxS ~1.14 and CzS ~1.8 which is much less than what you are quoting. What ride height you are running the calculation at?

I am not sure why CzS is so off respect to literature... :? #-o
I believe the car was setup the same as Perrin did - so 20mm front 50mm rear as measured at the reference plane. Ravelli did a MSc(?) thesis study with the Perrin and got a peak CzS of 3.48 at 10mm front 55mm rear. You're getting those numbers with the Perrinn?

In general you won't see real numbers quoted in literature because teams don't want that data out there, and there aren't many teams publishing peer reviewed articles. Gascoyne and Agathangelou wrote a paper in '98 with numbers for Tyrrell who by the publishing date were on their way out of the sport and selling their entry to BAR.
#aerogandalf
"There is one big friend. It is downforce. And once you have this it’s a big mate and it’s helping a lot." Robert Kubica

ggaggio19
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Re: CFD of F1T Modified PERRINN F1 Car

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jjn9128 wrote:
Wed May 27, 2020 8:34 pm
ggaggio19 wrote:
Wed May 27, 2020 3:21 pm
Excellent thread, really =D> =D> . I am taking this as a sort of baseline for my setup. Until now I am getting a CxS ~1.14 and CzS ~1.8 which is much less than what you are quoting. What ride height you are running the calculation at?

I am not sure why CzS is so off respect to literature... :? #-o
I believe the car was setup the same as Perrin did - so 20mm front 50mm rear as measured at the reference plane. Ravelli did a MSc(?) thesis study with the Perrin and got a peak CzS of 3.48 at 10mm front 55mm rear. You're getting those numbers with the Perrinn?

In general you won't see real numbers quoted in literature because teams don't want that data out there, and there aren't many teams publishing peer reviewed articles. Gascoyne and Agathangelou wrote a paper in '98 with numbers for Tyrrell who by the publishing date were on their way out of the sport and selling their entry to BAR.
What is the reference plane? I think I have probably got them wrong xD

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jjn9128
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Re: CFD of F1T Modified PERRINN F1 Car

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ggaggio19 wrote:
Thu May 28, 2020 9:11 am
What is the reference plane? I think I have probably got them wrong xD
The reference plane is the bottom of the car or z=0 as described in the rules - the only thing lower is the 10mm thick plank.
#aerogandalf
"There is one big friend. It is downforce. And once you have this it’s a big mate and it’s helping a lot." Robert Kubica

Jdempster
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Re: CFD of F1T Modified PERRINN F1 Car

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Vyssion wrote:
Wed Mar 13, 2019 10:09 am
Next update.

jjn and I have spent some time CADing and CFDing some of our own 2019 wings. Having exhausted the Perrinn model, we are now starting to slowly rebuild bits of it in the hopes of having our "own" F1 car model eventually. The FW has been deliberately kept not "too" aggressive in order to focus more on the outwash generation with representative strakes and endplates, whilst the RW still currently has the 2018-modified endplates (still 2019 legal) but with custom main plain and flap with centre attachment. The changes which were made by modifying the 2018 spec to the 2019 essentially saw reduced down and outwash behind the front tyres, along with quite a substantial shift in aero-balance towards the rear. As such, the current setting angles and the like are aimed at exploring the 2019 spec in CFD whilst trying to offset some of that rearward shift. (note, this will be covered in an article we've also written to be released shortly!!)

My meshing process I think is kind of beginning to get robust enough to decrease the turn around time required for new CAD to be meshed... with all the simplifications and "hacks" I'm having to do in order to not blow up my home computer, it has been very tempramental as to whether it will generate or not... hence any robustness in the process is a welcomed sight!! Typical convergence residuals are also improving slightly as we go which, once again, is all good news.

Finally, from here, Vanja is going to be joining in on the project and will be looking at creating some different bargeboards and/or floor as his first contribution. These images still have the standard Perrinn parts for that, however, hopefully as time goes on, more and more of this model will appear in various colours and replace the grey bits.

https://imgur.com/0hdJh2b.png
https://imgur.com/yjlgWHt.png
https://imgur.com/8WrH1sm.png
https://imgur.com/L1xxMnD.png
https://imgur.com/rohnIpc.png
Hi, i have been trying to clean the Perrinn cad model up ready for CFD, have you shared you modified version anywhere? You have done a great job

Jdempster
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Re: CFD of F1T Modified PERRINN F1 Car

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Also i was wondering you were able to apply an inflation layer on this car to better capture viscous drag effects, obviously this would lead to an increase in cell count massively and potentially in skewness too

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jjn9128
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Re: CFD of F1T Modified PERRINN F1 Car

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Jdempster wrote:
Thu Aug 20, 2020 2:49 am
Hi, i have been trying to clean the Perrinn cad model up ready for CFD, have you shared you modified version anywhere? You have done a great job
Hello, it's something we get asked a lot for this and our 2021(22) CAD model. We have discussed it internally and our standard answer to everyone is that we won't share any of our CAD. Tbf there's not a lot we did - obviously the big thing was adding the halo which I did my best to approximate at the time so is definitely not 100% accurate - there's a small issue around the Gurney flap in the rear wing, otherwise it was just a matter of removing some of the thin elements from the edge radii - but depending on your CFD/mesher that wont even matter.

Jdempster wrote:
Thu Aug 20, 2020 1:41 pm
Also i was wondering you were able to apply an inflation layer on this car to better capture viscous drag effects, obviously this would lead to an increase in cell count massively and potentially in skewness too
There is indeed a surface prism mesh, we don't half-arse our CFD :lol:
#aerogandalf
"There is one big friend. It is downforce. And once you have this it’s a big mate and it’s helping a lot." Robert Kubica

Jdempster
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Re: CFD of F1T Modified PERRINN F1 Car

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jjn9128 wrote:
Thu Aug 20, 2020 2:01 pm
Jdempster wrote:
Thu Aug 20, 2020 2:49 am
Hi, i have been trying to clean the Perrinn cad model up ready for CFD, have you shared you modified version anywhere? You have done a great job
Hello, it's something we get asked a lot for this and our 2021(22) CAD model. We have discussed it internally and our standard answer to everyone is that we won't share any of our CAD. Tbf there's not a lot we did - obviously the big thing was adding the halo which I did my best to approximate at the time so is definitely not 100% accurate - there's a small issue around the Gurney flap in the rear wing, otherwise it was just a matter of removing some of the thin elements from the edge radii - but depending on your CFD/mesher that wont even matter.

Jdempster wrote:
Thu Aug 20, 2020 1:41 pm
Also i was wondering you were able to apply an inflation layer on this car to better capture viscous drag effects, obviously this would lead to an increase in cell count massively and potentially in skewness too
There is indeed a surface prism mesh, we don't half-arse our CFD :lol:
You've done a great job, especially with the halo and the 2019 spec pieces, I ask about the CAD because I no longer have a solidworks license and its a big job to clean up the cad for PERRINN 2017 model. Do you have an old version of this car that is just cleaned up without all of the extra 2019 work that you have added (wheels simplified and sharp edges removed etc) ?

ggaggio19
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Re: CFD of F1T Modified PERRINN F1 Car

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jjn9128 wrote:
Thu May 28, 2020 7:09 pm
ggaggio19 wrote:
Thu May 28, 2020 9:11 am
What is the reference plane? I think I have probably got them wrong xD
The reference plane is the bottom of the car or z=0 as described in the rules - the only thing lower is the 10mm thick plank.
Just got back to this work...just a quick question if you can answer: how do you take the front and rear measure? I mean, if the car has got some incidence then the front and rear measures will vary depending on the x coordinate where you take the measurement. Is there a standard x position from where taking these measurements that you mentioned (i.e. 10mm front and 55mm rear)?

Thanks

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jjn9128
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Re: CFD of F1T Modified PERRINN F1 Car

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ggaggio19 wrote:
Thu Sep 24, 2020 4:19 pm
Just got back to this work...just a quick question if you can answer: how do you take the front and rear measure? I mean, if the car has got some incidence then the front and rear measures will vary depending on the x coordinate where you take the measurement. Is there a standard x position from where taking these measurements that you mentioned (i.e. 10mm front and 55mm rear)?

Thanks
The ride height is generally measured from the reference plane to the ground at the front and rear axle lines. You have to imagine the reference plane is projected to the front axle line as there's no bodywork there.

Vyssion prefers to measure the absolute minimum ground clearance so for him in our excel sheet I do a bit of trig to work out the height at the bottom of the skid at front of the tea tray, which is 430mm behind the front axle line and 10mm below the reference plane.
#aerogandalf
"There is one big friend. It is downforce. And once you have this it’s a big mate and it’s helping a lot." Robert Kubica

ggaggio19
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Re: CFD of F1T Modified PERRINN F1 Car

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jjn9128 wrote:
Thu Sep 24, 2020 4:37 pm
ggaggio19 wrote:
Thu Sep 24, 2020 4:19 pm
Just got back to this work...just a quick question if you can answer: how do you take the front and rear measure? I mean, if the car has got some incidence then the front and rear measures will vary depending on the x coordinate where you take the measurement. Is there a standard x position from where taking these measurements that you mentioned (i.e. 10mm front and 55mm rear)?

Thanks
The ride height is generally measured from the reference plane to the ground at the front and rear axle lines. You have to imagine the reference plane is projected to the front axle line as there's no bodywork there.

Vyssion prefers to measure the absolute minimum ground clearance so for him in our excel sheet I do a bit of trig to work out the height at the bottom of the skid at front of the tea tray, which is 430mm behind the front axle line and 10mm below the reference plane.
Thanks this really helps. I have actually decided to read the FIA rule as well (should have done earlier maybe...) :D #-o

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jjn9128
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Re: CFD of F1T Modified PERRINN F1 Car

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ggaggio19 wrote:
Mon Sep 28, 2020 8:32 pm
Thanks this really helps. I have actually decided to read the FIA rule as well (should have done earlier maybe...) :D #-o
Yeah reading the rule book should be point 1 :lol: It's a long and formidable document, especially these days, but will lead you to a greater understanding of why teams do what they do.
#aerogandalf
"There is one big friend. It is downforce. And once you have this it’s a big mate and it’s helping a lot." Robert Kubica