This work applies the volume-average mathematical operator over the buoyancy terms in the flow equations governing turbulent flow. Volume averaging is taken on both mean and turbulent fields. Derivations are carried out under the recently established double-decomposition concept. Results show that additional buoyancy generation term appears if both averaging procedures are applied simultaneously. Final modeled equations are based on a macroscopic k-e model for porous media. Results are compared with numerical data when available in the literature.