Aerodynamics plays a huge part in any F1 race be it the high downforce requirements of Monaco or the reduced-drag desires of Monza; each race also being at the mercy of the changeable weather conditions as we almost experienced this weekend in the Principality.
All these factors affect the performance of each car in many different ways – we’ve had 6 winners in 6 races in 2012 and in each you can see certain variables creating or assisting with the success, or failure, of the drivers and teams.
Now based on what I have posted about previously, aerodynamics (or at least the maths behind it) is complex enough based upon track requirements, weather, tyres, driver preference etc but you often hear about engine mapping also playing its part [F1 is fundamentally a sport, but if all could see the wizardry, physics and depth of mathematical detail supporting it, you'd think it were of NASA proportions].
So what is engine mapping?
Just before I delve into this, I’d like to state that the aerodynamic configuration for the car is determined by the circuit the car is about to hurtle itself around obeying the laws of motion determining the laws of aerodynamics giving an overall performance for the car. Simple. OK a tiny tweak here and there during a race but fundamentally unchanged.
Engine mapping is not a completely specific and nailed down undertaking and is generally discussed and illustrated in a ‘disconcertingly vague’ way but essentially it is the way the ECU allows and controls the engine to perform throughout a race. So, for example, you could be required to brake at the end of a long straight (low downforce, low drag) into a tight corner (higher downforce) and lift off the throttle, applying the brakes, but the ECU maintains the engine power output – the resultant effect of this is that the aerodynamic configuration is now having to work under completely different conditions as the energy output from the exhaust gases are vastly different and far hotter playing an altered role in the aerodynamic performance of the cars set up.
Similarly you could be safely leading the race and not have to ‘hammer’ the engine in order to maintain your lead, simply ‘cruise’ to the finish line.
This can have both a positive or negative effect on the car and needs to be simulated using CFD solvers to capture the increase in energy output and its effects downstream.
I guess most people would state that engine mapping should be set to ‘fast’ at all times as that is the name of the game – but any alterations can assist with fuel consumption on strategic final laps depending upon position – a final cruise to the chequered flag, as described above: or an adjusted power output to conserve tyre degradation.
Either way any change can play a huge part in the overall aerodynamic performance so (it clearly varies from team to team) a fast setting can aide one driver and visibly inhibit another. A main contributor to this is the position and profile, and indeed the downstream aero path, of the exhaust outlet – greatly effecting rear downforce if toward the centre of the car and providing grip if toward the rear.
For me, in my job, this adds complexity and also pushes the designers and aerodynamicist’s within each team to constantly improve the finer details of the ‘aerodynamic path’ of the airflow on race from start to finish accounting for all eventualities.
The mathematics are able to calculate for change by adding a further source term for energy and as I mentioned above CFD (Computational Fluid Dynamics) is the quickest and most accurate way of carrying this out.
More and more powerful compute clusters used by F1 teams are crunching more and more complex mathematical equations to ascertain whether or not the minute or massive changes created by the use of engine mapping techniques contribute toward the final success of each driver and team.
Also these changes play a knock-on effect on phenomenon such as Fluid Structure Interaction (FSI) – FSI is the interaction of some movable or deformable structure with an internal or surrounding fluid flow.
So in the case of an F1 car, the deformation of a front wing under acceleration or braking…… perhaps more on this again!