Hi,
I am studying and understanding the 3D-shaped floor of the new F1 and the effect in downforce for my degree final project. My intention is to perform an initial simulation with a F1 car prototype that I already have, note the aerodynamic coefficients and make a simple study so that later I can modify the floor in different ways to see the effect in the Cl and Cd in relation to the base model.
I am currently experiencing problems with the value of the Y+, my teacher of Fluid Mechanics told me that I need an Y+ value ideally below 10 as I am using wall functions and the K-omega SST model. I read the topics posted in this forum about the Y+ and used the simple equation of the Y+ to estimate the first layer thickness, then using the inflate boundary layer tool I performed simulations to check the y+ value.
As I was wasting a lot of core hours I reduced the mesh quality to this: (not sure if it’s enough).
The car is approximately 5 m long and 2 m wide, until I have set all the parameters I am performing the simulations with one side of the car and symmetry wall function on that wall.
For the rest of the mesh, I put a 6 in the slider finesse.
For the first run I went with this inflation settings, boundary conditions and steady simulation:
Y+ results (266 iterations)
Here the results:
2nd run:
In this case I run an entirely simulation (1000 steps):
For the next simulation I decided to put different inflation values according to the areas with the higher y+. For the wheels, front wing, wheel struts, side pots, moving wall and underfloor I used the same inflation settings with a thickness of 5x10-6 m, for the rest of the car 7x10-6 m.
The results: (600 iterations)
Note: Each time I have done a new mesh I had accidently overwitted the older one, so you are not able to see the mesh settings, the values come from my personal notes.
Almost all the body has a y+ higher than 10 in all the runs. All the simulations are steady.
The point here is that I don’t see a clear reduction in the y+ parameter even thought I have considerably reduced the first layer thickness, I must be doing something wrong, any tips, suggestions or help is appreciated.
Thanks