The teams brought many updates to Hockenheim, the penultimate race before the summer break. The changes, and their functions are explained from an engineering perspective here.

Williams

Williams brought a heavily updated floor and barge board package to Hockenheim.

También nuevo fondo para Williams Also new floor for Williams pic.twitter.com/E2nIuAkHOf — Albert Fabrega (@AlbertFabrega) July 25, 2019

As you can see the new floor features new longitudinal slots rather than multiple diagonal slots. Although one diagonal slot remains immediately preceding the rear tyre. The longitudinal slots are angled rather than holes straight through the floor. This means the air accelerated from above the floor (higher pressure) through the slots to below (lower pressure) will gain a sidewards velocity component. This will help towards preventing the ingress of air under the floor, which is detrimental particularly if it is the front wheel wake flow.

Nuevos bargeboards para Williams New bargeboards for Williams pic.twitter.com/6fBdW4UQ0t — Albert Fabrega (@AlbertFabrega) July 25, 2019

The FW42 barge boards are now much larger and complex in design. There is now a so-called ‘boomerang wing’ which is there to create some downwash in the flow as it travels towards the rear of the car around the sidepods. The traditional barge board section, which is a curved vertical section, is now split into multiple pieces, similar to a multiple-element wing. This possibly allows greater curvature of this section, whilst avoiding flow separation than a one piece design.

Mercedes

As previously mentioned, Mercedes turned up with multiple updates this past weekend. Because of this many people were expecting a dominant performance from the reigning champions however that was far from the case.

Concepto completamente nuevo para Mercedes en la pletina del ala posterior Completelly new rear wing endplate concept for Mercedes. pic.twitter.com/UJCCR7BefC — Albert Fabrega (@AlbertFabrega) July 25, 2019

Starting at the rear of the car, the rear wing endplates were changed. There was an increase in size and quantity of strakes on the outer face of the plate. These drive more upwash at the rear which helps with flow through the diffuser, as the diffuser and the rear wing are aerodynamically coupled, leading to more downforce. They will produce downforce themselves, although based on their size it will be such a small amount it is hardly worth mentioning. The more eye-catching change is the stepped section. Each edge in this area will produce a vortex which all off-set from one another vertically. The uppermost vortex will be rotating clockwise (at the right-hand end plate when viewed from behind) whereas all the others will be rotating in the opposite sense. These vortices will merge, resulting in a weaker vortex than if these cutouts weren’t present, reducing the induced drag.

At the rear of the floor there was a small change that saw the diagonal slots extended in length. It is further forward on the car that saw the most changes.

New larger turning vanes have been added, which are at a larger angle of attack than the previous design. There is also a smaller vane just behind the wishbone. All of these are there to create downwash in this area, at the expense of some lift. This directs a larger mass flow below/around the sidepods, leading to an overall increase in downforce.

Ahora sí, primera foto completa de la evo de Mercedes en los pontones. Yes. Finally full picture of Mercedes sidepods upgrades. pic.twitter.com/edWi4FP9ON — Albert Fabrega (@AlbertFabrega) July 24, 2019

Also around the front of the car Mercedes added some winglets, pointed out above, which will create an upwash outboard of the car, similar to that of the Haas and now Toro Rosso. This again helps with moving the wheel wake up and away from the car. As the low total pressure (energy), low velocity flow of a wake is detrimental to downforce production. These winglets are also producing a small amount of downforce themselves.

A small fin has been added on the foot plate of the FW end plate. Similar to the part Ferrari added a few races back.

toro Rosso

Toro Rosso had a very successful Sunday in Germany, due to some good driving and clever strategy but also in part down to some changes to the floor and barge boards. They added a small vertical section and a boomerang wing to the barge boards. The vertical section aiding in turning the flow outwards and generating some small vortices, rotating in such a way as to push flow outboard also. The boomerang wing producing some downwash in front of the sidepods. The longitudinal slots on the floor have increased in number, these have the same function as previously mentioned helping to mitigate against the ingress of air under the floor.

Nuevos bargeboards para Toro Rosso. Han añadido el boomerang en la parte superior New revised bargeboard for Toro Rosso. They added the boomerang on top pic.twitter.com/M2rOevhDFK — Albert Fabrega (@AlbertFabrega) July 25, 2019

Nuevo fondo plano para Toro Rosso en Hockenheim. Nuevos cortes y deflectores verticales añadidos. New floor for Toro Rosso in Hockenheim. New longitudinal slots and vertical deflectors. pic.twitter.com/61F0a8eCzL — Albert Fabrega (@AlbertFabrega) July 25, 2019