'F92AT - Double Floor' simulation project by yosukegb4


#1

I created a new simulation project called 'F92AT - Double Floor':

Simulation of Double Floor Sidepod


More of my public projects can be found here.


#2

Ferrari F92AT

F92AT was a Formula 1 car that Ferrari constructed for the championship of 1992.
The characteristic parts of the car are double floor sidepods.

I think F92AT is one of the most beautiful cars in the history of motorsports.
Contrary to its beauty, as far as the results show, the car did not have enough performance for winning the Formula 1 championship.

In this study, it is aimed to know the aerodynamic performance of F92AT by comparing with the general sidepod shape at that time.

Models

The original shape of F92AT was modeled as below.


In order to compare with the original "Double Floor" sidepod, "Single Floor" sidepods were designed as below.

  • Design Requirements for Single Floor Sidepod
    • No space between the sidepod and the underpanel -> 100mm lower position
    • Radiator intake of a general shape in 1992
    • Same shapes as far as possible
      • Same radiator size
      • Same radiator outlet on the side wall

Simulations

The simulations were calculated on SimScale page of the following link.


  • Conditions of the simulaltions
    • Speed : 30 [m/s]
    • Ride Height (Front-Rear) : 20mm - 35mm

Coefficients

  • Org Sidepod : F92AT Original Sidepod (Double Floor)
  • Lwr Sidepod : F92AT Sidepod 100mm Lower (Single Floor)

Body and Wheels

Coef. Org Sidepod Lwr Sidepod Difference Difference % Remarks
Cm 0.2589 0.2562 -0.0027 -1.1
Cd 0.9699 0.9677 -0.0022 -0.2
Cl -1.5741 -1.6746 -0.1005 6.4
Clf -0.5281 -0.5811 -0.0530 10.0
Clr -1.0460 -1.0935 -0.0475 4.5
CoP 0.6645 0.6530 -0.0115 -1.2
L/D -1.6229 -1.7306 -0.1076 6.6

Body Only

Coef. Org Sidepod Lwr Sidepod Difference Difference % Remarks
Cm 0.2483 0.2425 -0.0058 -2.3
Cd 0.6394 0.6512 0.0119 1.9
Cl -1.7724 -1.8630 -0.0906 5.1
Clf -0.6380 -0.6890 -0.0511 8.0
Clr -1.1345 -1.1740 -0.0395 3.5
CoP 0.6401 0.6302 -0.0099 -1.0
L/D -2.7722 -2.8607 -0.0886 3.2

In “Body and Wheels” comparison, all coefficients of “Lwr Sidepod” (Single Floor) shows better performance than those of “Org Sidepod” (Double Floor).

In “Body Only” comparison, Cd of “Lwr Sidepod” increases from Cd of “Org Sidepod”, but in “Body and Wheels” comparison Cd of “Lwr Sidepod” in “Body and Wheels” is almost the same with Cd of “Org Sidepod”. These mean that a part of the wheel drag occurring in “Org Sidepod” switched to the body drag in “Lwr Sidepod”.


Pressure on Surfaces

As a remarkable difference, the low pressure area at the bottom of the “Lwr Sidepod” underpanel is larger.

And the high pressure area at the “Org Sidepod” rear wheel front lower area is larger.


Radiator Flow Rate

Org Sidepod m3/s Lwr Sidepod m3/s Difference m3/s Difference % Remarks
0.5980 0.6601 0.0621 10.4

The radiator flow rate of “Lwr Sidepod” is also higher about 10%.

The comparison of the flow velocity distribution of these Radiators is shown in the figure below.


Sectional Flow Rates between Underpanel and Road

Because the flow rate between the underpanel of the “Org Sidepod” and the road was seen smaller from the state of the coefficients and the pressure, the sectional flow rates below the underpanels in each sidepod shape were calculated.

X mm Org Sidepod m3/s Lwr Sidepod m3/s Difference m3/s Difference % Remarks
1600 0.4976 0.5154 0.0178 +3.56
2500 0.6872 0.6969 0.0097 +1.41

It was confirmed that the flow rate between the under panel of “Org Sidepod” and the road is smaller.


Streamlines around Sidepods

The flow around the “Org Sidepod” seems to be a little smoother than that of “Lwr Sidepod”.

A characteristic difference of these streamlines of the two sidepods
was seen in the streamlines starting from height 60 mm.

The air that has been dammed up around the radiator inlet at the front of “Lwr Sidepod” and flows more under the underpanel.

On the other hand, the air of “Org Sidepod” flows smoothly between the sidepod and the underpanel, and flows less under the underpanel than that of “Lwr Sidepod”. Therefore, the double floor “Org Sidepod” does not increase the flow velocity below the underpanel and the low pressure area where the downforce occurs is small.

And in addition, the clean flow around the dobule floor sidepod and underpanel of “Org Sidepod” hits the the front lower area of the rear wheel and increases the lift and the drag of the rear wheel.


Coefficients - 60[m/s]

Simulations with the flow velocity of 60 [m/s] were also calculated.
The trends of the results were the same as those in the cases of 30 [m/s].

  • Org Sidepod : F92AT Origin RH20-35mm
  • Lwr Sidepod : F92AT Sidepod 100mm Lower RH20-35mm

Body and Wheels

Coef. Org Sidepod Lwr Sidepod Difference Difference % Remarks
Cm 0.2632 0.2578 -0.0054 -2.1
Cd 0.9712 0.9697 -0.0015 -0.2
Cl -1.5825 -1.6802 -0.0977 6.2
Clf -0.5280 -0.5823 -0.0543 10.3
Clr -1.0545 -1.0979 -0.0435 4.1
CoP 0.6663 0.6535 -0.0129 -1.3
L/D -1.6294 -1.7327 -0.1033 6.3
RF 1.2080 1.3400 0.1321 10.9 Radiator Flow m3/s

Body Only

Coef. Org Sidepod Lwr Sidepod Difference Difference % Remarks
Cm 0.2532 0.2448 -0.0084 -3.3
Cd 0.6386 0.6510 0.0124 1.9
Cl -1.7842 -1.8728 -0.0885 5.0
Clf -0.6389 -0.6916 -0.0527 8.2
Clr -1.1453 -1.1812 -0.0359 3.1
CoP 0.6419 0.6307 -0.0112 -1.1
L/D -2.7939 -2.8767 -0.0827 3.0

Conclusions

  • F92AT double floor sidepod performance
    • All coefficients : Worse
    • 10% lower radiator flow rate
    • Less body drag but more wheel drag
  • Fluid phenomena occurring on the double floor of F92AT
    • Smoother flow around the dobule floor sidepod and underpanel
      • Hit on the front lower area of the rear wheel
        • Increase of the lift and the drag on the rear wheel
    • Less flow under the underpanel
      • Decrease of the flow velocity below the underpanel
        • Small low pressure area where the downforce occurs

#3

Hey @yosukegb4,

Awesome project! Really great analysis on how a simple aerodynamic change can help with the performance of the car!

From your results it seems like the balance of the car shifts forwards for the single floor as the rear wheels now has a slightly lower pressure value. I wonder if this is enough to have adversely affected the rest of the package if it was implemented :thinking:

A quick question about CL and CD values. Is there away to take a look at the % difference in CL CD to determine possible lap time gains on specific circuits? Would be interesting to see how the significant increase in downforce (5%) for the single floor would help the speed of the car and by how much considering that there is a slight CD increase of 1.9% along with better flow management towards the rear and into the radiators. I would suspect the performance gains would be substantial for the designers to implement such an idea.

With that being said, why didn’t they consider this? Was it regulatory or some other reason?

Also where did you get your geometry? I always wanted to embark on projects like this but the daunting complexity of the CAD models involved especially for modern F1 cars does make me apprehensive :sweat_smile:

Otherwise brilliantly done project. I look forward with great eagerness to your next project! Hope to do something like this soon!

Cheers!

Regards,
Barry


#4

Hi @Get_Barried !

Thank you for the reply!

  • Forward balance shift for the single floor
    • Forward shift of the balance is mainly due to the change of the pressure under the underpanel.
    • Generally in formula cars there are less ways to generate front downforce compared with the rear downforce. So I think this forward shift of the balance is beneficial.
    • The lower center of gravity for the single floor is also good for vehicle dynamics.
  • Coeffcients and Track Performance
    • I have no experience of a track engneer so I cannot say about a specific performance improvement on the ciecuit. Anyway, it can be said that aerodynamic engineers will consider adopting to actual vehicles even if the performance improvement is less than 1% in a wind tunnel.
    • And my CFD simulations are not as accurate as wind tunnels. I think that there are errors of about 1% to 5%.
  • Why was the double floor adopted at that year?
    • It is said that engineers at the time tried to improve the car performance by fastening the flow of the diffuser with the air flow between the sidepod and the underpanel.
    • I also do not know well about the environment in 1992, but I guess that there are much differences with now in computing capacities, wind tunnel measurement technologies and so on. Therefore, there seems to be a lot of parts that depend on intuition of engineers compared with now.
    • In the next year 1993, designers and engineers adopted conventional single floor sidepods for F93A. :sweat_smile:
  • Car Geometry

Best,
Yosuke Yamamoto


#5

Hi @yosukegb4,

Thanks for the detailed and insightful reply! I’ve learned quite a bit from that!

Really cool that you modeled the car from scratch like that. Again, looking forward to more projects from you! If you need some help from my end I’d be happy to offer a free hand!

Cheers.

Regards,
Barry