  We study fluctuations of all co-existing energy exchange/transfer/transport
processes in stationary periodic turbulence including those which average to
zero and are not present in average cascade theories. We use a Helmholtz
decomposition of accelerations which leads to a decomposition of all terms in
the K\'arm\'an-Howarth-Monin-Hill (KHMH) equation (scale-by-scale two-point
energy balance) causing it to break into two energy balances, one resulting
from the integrated two-point vorticity equation and the other from the
integrated two-point pressure equation. The various two-point acceleration
terms in the Navier-Stokes difference (NSD) equation for the dynamics of
two-point velocity differences have similar alignment tendencies with the
two-point velocity difference, implying similar characteristics for the NSD and
KHMH equations. We introduce the two-point sweeping concept and show how it
articulates with the fluctuating interscale energy transfer as the solenoidal
part of the interscale transfer rate does not fluctuate with turbulence
dissipation at any scale above the Taylor length but with the sum of the
time-derivative and the solenoidal interspace transport rate terms. The
pressure fluctuations play an important role in the interscale and interspace
turbulence transfer/transport dynamics as the irrotational part of the
interscale transfer rate is equal to the irrotational part of the interspace
transfer rate and is balanced by two-point fluctuating pressure work. We also
study the homogeneous/inhomogeneous decomposition of interscale transfer. The
statistics of the latter are skewed towards forward cascade events whereas the
statistics of the former are not. We also report statistics conditioned on
intense forward/backward interscale transfer events.
