[shashanktiwari619]

I am running a LES simulation for a flow over bluff body where in I monitor drag and lift coefficient w.r.t time. I switch on the 'Data Sampling for Time statistics' after my converge fairly well which is at around 1 secs (my time step is 1e-5). I have observed that the value of drag coefficient monitor show a lot of oscillation around the previously obtained time data of drag coefficient after I switch on the 'Data Sampling'. why is it so?? I have attached the time vs drag coefficient plot where I switch on the time statics after around 1.8 secs and the oscillations are clearly visible.
I get that switching on data statistics gives RMS and mean values of all variables for every time step specified. But why should it effect the drag monitor values??Am I missing out in understanding something here??