  Expansions in the oscillation modes of tidally perturbed bodies provide a
useful framework for representing tidally induced flows. However, recent work
has demonstrated that such expansions produce inaccurate predictions for
secular orbital evolution when mode damping rates are computed independently.
We explore the coupling of collectively driven modes by frictional and viscous
dissipation, in tidally perturbed bodies that are both non-rotating and rigidly
rotating. This exploration leads us to propose an alternative approach to
treating the damping of tidally driven oscillations that accounts for
dissipative mode coupling, but which does not require any information beyond
the eigenfunctions and eigenfrequencies of adiabatic modes.
