  We present a formalism for investigating the interaction between pmode
oscillations and convection by analyzing realistic, three-dimensional
simulations of the near-surface layers of the solar convection zone. By
choosing suitable definitions for fluctuations and averages, we obtain a
separation that retains exact equations. The equations for the horizontal
averages contain one part that corresponds directly to the wave equations for a
1-D medium, plus additional terms that arise from the averaging and correspond
to the turbulent pressure gradient in the momentum equation and the divergence
of the convective and kinetic energy fluxes in the internal energy equation.
These terms cannot be evaluated in closed form, but they may be measured in
numerical simulations. The additional terms may cause the mode frequencies to
shift, relative to what would be obtained if only the terms corresponding to a
1-D medium were retained---most straightforwardly by changing the mean
stratification, and more subtly by changing the effective compressibility of
the medium. In the presence of time dependent convection, the additional terms
also have a stochastic time dependence, that acts as a source of random
excitation of the coherent modes. In the present paper, we derive an expression
for the excitation power and test it by applying it to a numerical experiment
of sufficient duration for the excited modes to be spectrally resolved.
