When the 2022 Formula 1 season commenced five months ago in Bahrain it was the dawn of a new era for the sport due to the long-anticipated new technical regulations, with ground effects still offering a plethora of opportunities waiting to be explored.
Although teams have made remarkable progress with the competitive development of their designs it is reasonable to assume that because it is only the first year of this novel framework, its performance threshold is far from being approached.
Whilst F1’s governing body, the FIA has already revised the technical regulations for 2023, primarily due to safety concerns associated with the porpoising phenomenon, the changes are not severe enough to impact the teams’ 2023 design direction.
Consequently, a development continuity exists that places importance and reliance on their development plans still outstanding for the remainder of this season.
The exploitation and refinement of the ground effect will be the major area of development that gives the teams the best performance results and value for money at this stage of the technical regulation maturation.
Ground Effect Changes
To control porpoising next season revisions have been made to the 2023 technical regulations that raise and stiffen the underfloor edge and raise the diffuser throat height. Even though it hasn’t been explicitly stated the obvious intention is to minimise the risk of the throat flow stall that causes violent underside pressure increase and its associated rapid increase in ride height.
This is in accordance with one of the fundamental physical relationships of the ground effect which is that ride height and downforce are inversely proportional.
What that means is that as the ride height increases, the downforce the ground effect produces is decreased.
Ground Effect Downforce Is More Than About Just Ride Height
Nevertheless, whilst what we observe as the primary behaviour of ground effect is based on one of the most important tenets of fluid dynamics, the Bernoulli Principle, it is not the only physical phenomenon occurring in the ground effect that produces downforce, as a concept called Couette Flow comes into play as well.
A simple way of describing Couette flow is considering the forward-moving car as the frame of reference. As the car moves forward the ground is moving backwards in comparison to the reference frame, and as the ground moves, it pulls the layer of air above along with it as well, causing it to move faster.
The relative motion between the ground boundary layer and the venturi tunnel top surface boundary layer creates a shear stress between the air layers and an associated pressure gradient that results in downforce.
Avenues for further refinement expected in 2022-2023
To counter a raise in ride height teams have been designing a degree of flexibility into their composite floor edges, particularly in the area between the venturi tunnel entry and the leading edge of the rear tyre, which produces the same effect as lowering the ride height of the car.
Even though the 2023 technical regulations require stiffer and less flexible floors, particularly at the edges, teams will still design in flexibility to reach the allowable limit, simply because the performance gains in doing so are tangible.
Another area of development being pursued by all the teams in 2022 is the positioning of flow conditioning appendages and protrusions in the underfloor edges that produce rearwards moving vortices of turbulent flow that are cleverly used to effectively seal the floor edge, and consequently the venturi tunnel so that downforce generation is maximised.
By conditioning and directing the venturi tunnel throat incoming flow to a more laminar condition the boundary layer separation that leads to the flow stall that induces porpoising can be minimised and in some instances even almost eliminated completely, as evidenced by one team in 2022 which has not seemed to have suffered from it at all.
The conditioning of the incoming throat flow, and the outgoing flow at the diffuser exit, to a more laminar condition, will be a big emphasis in development for most of the teams for the remainder of 2022, and into 2023.
In a similar manner, there will be a significant emphasis by the teams in maximising downforce generated through the Couette Flow, which will be achieved by careful geometrical detail at the interface of areas such as the monocoque floor and sides and the underfloor that induces less turbulence in the laminar venturi flows, evidenced in such detail as the tea that has never suffered from porpoising at all in 2022 to date.