Quote:
Originally Posted by Vman455
As I mentioned in another thread here recently, those fins are not VGs. Toyota first used them on the 3rd gen Prius in 2010, and stated in the press materials that they improve directional stability--in other words, they are straightening vanes, similar to but not as pronounced as those seen on hypercars. Here's the 2015 Nissan LMP1 Le Mans car:
Toyota uses them on the current Prius, Camry, Corolla, Sienna, and Avalon.
Here are the diffuser vanes on the current Nissan Leaf, larger than Toyota's but with the same function:
VGs are smaller, since they don't need to protrude beyond the boundary layer, and shorter, since they aren't directing airflow but disrupting it slightly. |
The primary purpose of strakes in an LMP1 diffuser is to segregate the flow fields considering the relatively dirty flow outboard near the spinning rear wheel. The secondary function is to generate vortices while in yaw. Some teams cut them short of the diffuser trailing edge or have cutouts and notches in them in order to further promote yaw-induced vorticeis. In LMP1 you're limited to one pair that must be parallel to car CL.
Short of diffuser TE:
Notch in strake TE:
Holes in strake:
In the recent past, when there were few restrictions on their design, they were designed as vortex generators primarily.
