Force India VJM11

[Vanja #66]

If only someone got a photo of Perez with fences the same way, flow viz fully air-formed and everything.

[ScrewCaptain27]

[IamLegend]

CFD correlation problems again!

- One of the problems it has admitted to is a lack of correlation between the windtunnel/CFD and the racetrack, with technical director Andy Green saying "the tunnel and CFD match, but unfortunately they don't match reality".

https://www.autosport.com/f1/news/13547 ... ough-start

Looks like this issue can take a while to iron out, let's see how it goes.

https://www.autosport.com/f1/news/13537 ... india-back

[Maritimer]

How can teams lose the ability to match simulation to reality year on year? Always just sounds like a cop out to me to save face instead if owning that they dropped the ball. Does CFD change that much every 12 months?

Edit: How is this a useless comment? So many passive aggressive people on these boards...

[IamLegend]

How can teams lose the ability to match simulation to reality year on year? Always just sounds like a cop out to me to save face instead if owning that they dropped the ball. Does CFD change that much every 12 months?

Well I think it's up to the individual to construe what it means, but there is progress from race to race. First race they barely could get out of Q2, in China they got one of the cars to start in P8, ahead of both the Haas,TR and McLaren cars. Barring the opening lap shunts with the lead car starting in the awful option tires, I think both cars were in the position to capture some points. I hope they can resolve the issue with the rear-end grip.

[Ashwinv16]

How can teams lose the ability to match simulation to reality year on year? Always just sounds like a cop out to me to save face instead if owning that they dropped the ball. Does CFD change that much every 12 months?

Well I think it's up to the individual to construe what it means, but there is progress from race to race. First race they barely could get out of Q2, in China they got one of the cars to start in P8, ahead of both the Haas,TR and McLaren cars. Barring the opening lap shunts with the lead car starting in the awful option tires, I think both cars were in the position to capture some points. I hope they can resolve the issue with the rear-end grip.

Also remember for this year the car's side pods were reduced in size and as seen from pictures posted on this forum, they seem to have problems with flow separation. When they decreased the sidepods' size, they had to change how the sidepods received the air and how it flowed around and over it. They had to make sure that the air sticks with the contours of the sidpods. Thus they now have to anlayze new CFD data for the new Sidepods to ensure the flow is attached and performance is gained, so different values(data) from 2017. Unfortunately these values weren't matching with reality and due to this irregularity the flow being separated from the sidepod at certain instances was causing turbulent air to flow to the back of the car disrupting the flow around the rear wing, diffuser, suspension arm, top of the floor etc...

By Bahrain they fixed that(Thus better pace), but apparently that was not enough as the new front wing they brought did'nt work. Thus they couldn't continue with the new front wing as an unstable rear end will only become more confusing when the flow coming to it is changed by the new front wing(Thus a new set of data which won't be helpful when you can't fix the old one, which is why they did'nt get any improvements in the first place with the new front wing, cause they realised there is still something wrong with the back end of the car). And so in China they focused on the flow over the top of the diffuser aka the floor which is why they were testing fences to stop the flow from separating from under the sidepods and tweaked the diffuser to help work with the new way in which the air travels through those points.

Force India tested some fences on Checo's car in P2, they used flow viz as well, but I haven't seen photos of it. This suggests they have some (separation?) issues in coke-bottle area. As they use the same (or similar) diffuser as final-spec in 2017 and they have rear-end issues, these fences are quite suggestive.

Did it work?, not sure as China is never really a great track for Force India but Perez's qualifying pace indicates that they are back in form and the next race is Azerbaijan which really suits this team, so will have to wait and see.

[Vanja #66]

Not sure if they were used in the race, hard to spot them really.

[IamLegend]

How can teams lose the ability to match simulation to reality year on year? Always just sounds like a cop out to me to save face instead if owning that they dropped the ball. Does CFD change that much every 12 months?

Well I think it's up to the individual to construe what it means, but there is progress from race to race. First race they barely could get out of Q2, in China they got one of the cars to start in P8, ahead of both the Haas,TR and McLaren cars. Barring the opening lap shunts with the lead car starting in the awful option tires, I think both cars were in the position to capture some points. I hope they can resolve the issue with the rear-end grip.

Also remember for this year the car's side pods were reduced in size and as seen from pictures posted on this forum, they seem to have problems with flow separation. When they decreased the sidepods' size, they had to change how the sidepods received the air and how it flowed around and over it. They had to make sure that the air sticks with the contours of the sidpods. Thus they now have to anlayze new CFD data for the new Sidepods to ensure the flow is attached and performance is gained, so different values(data) from 2017. Unfortunately these values weren't matching with reality and due to this irregularity the flow being separated from the sidepod at certain instances was causing turbulent air to flow to the back of the car disrupting the flow around the rear wing, diffuser, suspension arm, top of the floor etc...

By Bahrain they fixed that(Thus better pace), but apparently that was not enough as the new front wing they brought did'nt work. Thus they couldn't continue with the new front wing as an unstable rear end will only become more confusing when the flow coming to it is changed by the new front wing(Thus a new set of data which won't be helpful when you can't fix the old one, which is why they did'nt get any improvements in the first place with the new front wing, cause they realised there is still something wrong with the back end of the car). And so in China they focused on the flow over the top of the diffuser aka the floor which is why they were testing fences to stop the flow from separating from under the sidepods and tweaked the diffuser to help work with the new way in which the air travels through those points.

https://ibb.co/gp061n

Force India tested some fences on Checo's car in P2, they used flow viz as well, but I haven't seen photos of it. This suggests they have some (separation?) issues in coke-bottle area. As they use the same (or similar) diffuser as final-spec in 2017 and they have rear-end issues, these fences are quite suggestive.

Did it work?, not sure as China is never really a great track for Force India but Perez's qualifying pace indicates that they are back in form and the next race is Azerbaijan which really suits this team, so will have to wait and see.

It all adds up, good analysis and summarization @Ashwin, this clears things up!

[BloodLad91]

According to AMuS vjm11 has airflow separation problem in coke bottle region and spain update will solve the problem.

https://www.auto-motor-und-sport.de/for ... tenkasten/

[ScrewCaptain27]

Low-DF front wings, one with only two upper flaps:

Medium-DF rear wing:

They have also added a small strake on the bottom of the sidepod, presumably to clean airflow going into the coke-bottle:


Via Albert Fabrega

[dren]

They're having flow attachment issues around the sidepods to the rear. That strake is there likely to help with that.

[fsliv]

Does anyone know if they used the new front wings?? Thanks

[Sidhartha.techie]

Does anyone know if they used the new front wings?? Thanks

No, they won't be using that till next race weekend atleast, The FW they are using in Baku is the old one with the top most plate removed. Only new part which might not be track specific is Baffles

[IamLegend]

Does anyone know if they used the new front wings?? Thanks

No, they won't be using that till next race weekend atleast, The FW they are using in Baku is the old one with the top most plate removed. Only new part which might not be track specific is Baffles

Sergio said towards the end with the SS tires he was able to get 500th of a second on Kimi and Vettel, so they are definitely on their way up. I'll post the link to the interview if I can find it.

[Samraj_official]

Does anyone know what sort of upgrades are FI going to bring to Barcelona??

Since they have airflow problem around sidepods,scarbs said they either have to increase the size of sidepods or decrease the size of sidepods( total repackaging of the internal cooling and components)

So what way are they going to go??