“…In this subsection, we derive the time-dependent higher order estimates, which are necessary for the global existence of classical solutions. The procedure is similar as that in [3,19,20], and we sketch it here for completeness. From now on, assume that the initial energy C 0 ≤ ε 6 , and the positive constant C may depend on T, µ, λ, ν, a, γ, ρ ∞ , ρ, Ω, M 1 , M 2 , ∇u 0 H 1 , ∇H 0 H 1 , ρ 0 − ρ ∞ W 2,q , P (ρ 0 ) − P ∞ W 2,q , g L 2 for q ∈ (3, 6) where g ∈ L 2 (Ω) is given by compatibility condition (1.10).…”