Brief and one-time return to limited CFD trials like about a year ago, this time for W14. The CFD simulation is not an accurate representation of the whole car and is directed at understanding, to the best of simulations "ability" (ie comparability to actual car), of the major aerodynamic phenomena surrounding W14 sidepod design including the mid wing and it's influence. Some comparisons will be made to W13 launch spec, just as a curiosity. Also note, to try and reduce floor leading edge separation I made a change to front wing 3rd flap angle and separation was reduced, but not eliminated.
There are several interesting elements to take note of. First of all, slight changes to pressure distribution on sidepods themselves, made by clear geometry transition from slanted to vertical and resulting radii transition. This speeds up the airflow, creating lift - like all sidepods experience somewhere on their surface. Along with that, sidepods also seem to have a geometry that reduces external drag (especially compared to W13 raced zeropods).
Another change in pressure distribution is the rear tyre, where the stagnation zone is clearly smaller. This is influenced by the mid-wing-shed-vortex. While actual car is likely to experience a different influence of this vortex (I believe it hits the tyre slightly lower) it remains and could be an important feature. Why I believe it hits the tyre lower can be seen on this plot:
This vortex in this simulation is also dangerously close to the rear wing and I am certain this would not be the case in reality. It could result in unacceptable losses and I believe wings downwash is stronger and drawing the vortex further down. If it hits the tyre lower, it could also reduce rear tyre lift along with rear tyre drag - sounds like something worth achieving.
The downwash is very strong even in this simulation, as expected. It looks like the idea of the mid wing is to draw a large amount of clean air towards the diffuser fences. With proper conditioning, it could help diffuser performance significantly and ensure rear tyre squirt doesn't come close to the diffuser. Another concept worth chasing.
Seeing how W13 rear bodywork was developed around zeropods, it certainly looks like minimising their size could lead to massive diffuser gains, since you are now drawing a lot of clean and high-energy air where it can generate a lot of downforce. W14 sidepods look to be increased in size to tackle floor structural instability issues, but only to a minimum needed so the downwash is the least disturbed.
Final plot is something I want to bring note to - mid wing also generates decent drag. Entire rear/top surface is low pressure, while front/bottom is slightly above ambient. If there was a critical situation with W13 ride height, where combined effect of downwash air and diffuser performance is nowhere near as effective as expected due to higher ride height - you are still stuck with extra drag of the mid wing. This was certainly one of the causes of high drag of W13, along with big front and rear wing angles and that traditionally big airbox.
All in all, W14 is definitely an improvement over W13 regarding drag (which the team mentioned and we have here confirmed) and if Mercedes manages to extract floor downforce without as much trouble with bouncing, 2023 should be much better for them. How better also depends on the competition.
