While Renault has been the trend setter for aerodynamics in so far this season, for once the French team has adopted something seen at another team already. As early as last year, Toyota introduced the air guiding panels at the front top of the sidepods. Renault have now developed an element similar to that of Honda. It functions by reducing turbulence from the front wheel and guiding air properly around the sidepod. As for Renault, that means downward, in a bend towards the flip-ups positioned in front of the rear wheels.
Formula One car development blog
Renault have brought a new aero package to Canada including several obvious changes to the car. One of these are the "ears" on top of the nose which have now changed from a single element to a double element wing. As the trailing edge is pointing downwards, this element is not meant to produce any downforce but merely guide the air better towards the cockpit area. Practically, the first element of this ear is attached to the replaceable nose cone section, while the trailing element is part of the monocoque structure.
Also at Renault is the new rear wing, that similarly to McLaren's is a fully horizontal element. In contrast, previous rear wings at Renault had its main flap curved upwards in the centre of the car. It appears as if this simpler wing generates less drag, a feature that is highly needed at both American circuits. We may expect the curvatious wings to reappear at Magny-Cours, France.
Flexing and stalling wings have been a hot topic in F1 this year. While Ferrari and BMW were asked to strengthen their rear wings, some of the designs also feature a movable wing so that the slot gap between the two horizontal elements gets closed and hence makes the wing stall. In order to prevent these performance gains, the FIA mandated slot spacers that prevent the gap to be closed. It is for all teams a carbon element that connect to both the upper and lower element and makes their relative position fixed.