Hi,
As part of my bachelor’s thesis I need to simulate on gazebo a Glider modelled in a CAD software based from a real small RC Glider.
I am trying to do what this tutorial explains.
Here is where Simscale comes in play:
To get a linearisation for the alpha/lift curve, alpha/drag curve and the alpha/moment curve what I am doing is rotate the STLs at different angles of attack ( say 0, 2.5, 5, 7.5, 10, 12.5) and then calculate the coefficients for each STL.
This process is tedious since i gotta do this for 5 control surfaces and the fuselage. But i guess there isnt a way around ¯(°_o)/¯ ?
After that, I think it should be enough to do a linear regression to get the ratio of each linearisation.
This is my project.
My questions are:
-
Am I using the right turbulence model? Im using incompressible LES Spalart-Allmaras with transient time dependecy (the only option available for LES Spalart-Allmaras). The velocity of the flow is relatively slow, 6-7 m/s. I was also thinking that maybe the laminar turbulence model would suit for the first angles, up to 9/10 deg, after that, I guess I should use a different turbulence model, since the laminar flow starts to break at higher angles, correct?
-
I ve tried to calculate the coefficients for the elevator, as seen in the project. Those are the plots.
AoA 0:
AoA 5:
**AoA 10: **
AoA 15:
I dont know how to validate the data, they seem to coverge but I dont know if that is a valid argument to validate the data.
How could I validate it?
Here are the Residuals for the AoA 15.
The p value converges againt 0.5, what does this mean?
- Here is a plot on excel of the coefficient of lift. (There is not a linear regression, it is only a connecting the points - plot)
Why does it go back up? Is there a convergence problem for the simulation on the configuration AoA 15?
Or maybe the error is on the simulation for the configuration AoA 10 and there isnt a break of the laminar flow yet?
I know that I should do more simulations for several AoA configurations to get a better linear regression, but I dont want to use many computing hours while i dont know if the configuration of the CFD simulation is right.
Please, help me 
Thanks in advance,
Alejandro.