OLAF Module ( about velocity speedup)

[robytian]

Dear @ebranlard and @kshaler
I would like to ask you about the four options of VelocityMethod in SPEEDUP OPTIONS in the OLAF.dat file:

1. which method do you prefer to use
2. If I want to focus on the analysis of the flow field how many methods should I use?
3. Am I correct in understanding that the calculation speed is 4>2>1>3 and so is the calculation accuracy?
4. I have done a lot of simulations, and method 3 is almost impossible to calculate at the end, and method 4 is very easy to make the vortex filaments disperse
5. I am building 2 turbines at the same time, and I would like to focus more on the flow field analysis and make sure the calculation speed is not too slow, which method do you recommend.
   6.What does TreeBranchFactor stand for, I didn't read it in the manual.
   Thanks too much.