Dear @Kamesh, welcome to the forums.
I could not load the pictures. Also, it is important to attach your case link.
You need to understand the nature of the solver you are using ( I suppose you are using a steady-state solver). As @ggiraldof mentioned here: CFD Result Inconsistency, “Please bear in mind that at the first iterations it is normal to have big variations, and usually the convergence is evaluated on the last iterations.”.
So if you are indeed using a steady-state solver, the “s” does not represent physical seconds but # of iterations.
After a large number of iterations, fluctuations likely indicate transient behaviour (check out this post): Convergence issue - #4 by SBlock