Surface effects and turbulent pressure

The application of the full potential stellar seismology is made difficult by improper modelling upper-most layers solar-like stars and their influence on modelled frequencies. Our knowledge these so-called ‘surface effects’ has improved thanks to use 3D hydrodynamical simulations, however, calculation eigenfrequencies relies empirical models for description Lagrangian perturbation turbulent pressure, namely: reduced-? 1 model (RGM) gas-? (GGM). Starting from fully compressible turbulence equations, we derived both GGM RGM using a closure flux kinetic energy. We find that originate two terms: source pressure due compression produced oscillations divergence pressure. also demonstrate they are compatible with adiabatic approximation and, additionally, imply number questionable assumptions, mainly respect mode physics. Among other hypotheses, it necessary neglect dissipation energy into heat buoyancy work.