Stall modelling using 2DClmax

[Séraphin Remy]

Hi everyone, 

Is it possible to have more information about the stall model with the 2D Clmax please ? 

I made some testing and results are good overall : 

- ASK 21 computed stall speed flaps retracted : 74km/h vs 74km/h in flight manual

- DR400 computed stall speed flaps retracted : 94km/h vs 94km/h in flight manual

2D Clmax are computed with XFLR5.

However, I noticed some behaviours that I don't really understand : 

 - computed local Cl is almost always overshooting the 2D Clmax by ~10% : why is that ? is the 2DClmax the value of the maximum or the maximum value in linear range ? 

 - how is the Cl evolution calculated beyolnd 2DClmax ?

 - what is the influence of Cl0 supposed to be ? 

Also, I made some trials with flaps deflected (on the DR400 model) : 

 - computed CLtot is totally wrong but mainly due to a very negative local Cl at junction between wing, so I took the .lod file and recomputed the total CL manually (2*sum(Cl*dArea)/S_wing... good ?). But even like this, taking the raw data, the CL computed is higher than the CLtot from VSP. Do you know where it could come from ?

Thank you in advance, best regards,

Séraphin REMY