# Questions_Log
Date 30/03/2022

Q1. What is implicit diffusion?

Q2. In the test case of Y2, Why did we use two rotors very close to each other?

Q3. If I explicitly put the refinement level and choose the cartesian coordinates and slices then what is function of refinement level here?

Q4. What is Sponge layer?

Q5.Why is rotor centre yawed, ie not at 0,0,0 but at 0, 0.43xxxxx , 0 ?

Q6.Dump time vs Iter info time?

Q7. Why can't BHAWK run saveral turbines, I understand the complexity but not the problem involved, if I increase the domain and put another turbine, it shsould work right?

Q8. What exactly is this actuator position? - Actuator sets 5.00, 30,00, 60,00.

Q9.The convergance of Profiles in the diagram

It should be more of converged I feel, I speculate 2 things for this -
-- the flow is not fully developed in beginning, we didn't give enough time for flow to develop in this domain
-- the power didn't converge

With these two I think if I wait for flow to develop the power I would get is reduced one. Why is it like that.
How much time do u think the flow needs to develop.
According to me to fully develop the Turbulence inside a channel flow, its roughly 6 times the flow to completely pass through channel once, here firstly it's not a confined channel (even though computational model is like a channel). If I take it 6 times the flow to pass through this domain, it would be roughly 250 seconds, just to develop the flow. Would that be correct to say or you use a different method.

**Q10.** Why is the velocity profile undeveloped, So it means we need to first run without turbine so the turbulence can develop and we get fuller profile and then we can turn on the turbine?

**Q11.** How much time should I run this turbine simulation? 600 seconds?

Q12. Why is the Q Criterion and the Angular rotational velocities values are so so low?

Q13. Why is the Lift, Drag and coefficients are zero at Actuator position 5.00 but not at 30.00 and 60.00.

Q14. We are using Annular probe here, and for that we use certain number of points in annular, but wont they contradict with the mesh if its not points and just the annular surface?

Q15. What is use of Grid partitioning and NElementgroup in serial runs. what does those 1000 value actually signify, is it the actual cells?

Q16. What is the significance of Rotor wake center mentioning explicitly. The wake will propogate according to NS. So is this the post processing part to capture the wake and velocity histogram etc?