Then velocity of, the average velocity of water in that circumference, I can write v dash r equal to v r theta v theta divided by 2 pi from 0 to 2 pi. At all thetas, I integrate the velocity and take the, this is basically taking average. This is at one radius R. So, the overall wake over the whole propeller disc will be if I integrate this over R. Am I right? So, that can be given as 1 by pi R square minus root square 0 to 2 pi and this R b to R which is equal to, we have found out this V dash R. That integrated over the whole radius. That is all we have done from the boss to the propeller d.