The pressure equation on almost every time slice #
prop:lps-smoothing: let u be a strong solution with square-integrable space-time weak
derivatives ∇u, ∇²u, ∂ₜu and pressure p. Testing the equation against separated fields
χ(t) ψ(x)
shows that for almost every time, and for every smooth compactly supported spatial field ψ,
∫ (∂ₜu - Δu + (u·∇)u)(t) · ψ = ∫ p(t) div ψ.
The nonlinear term is moved onto (u·∇)u slice by slice, where u(t) ∈ H² is solenoidal.
Hence at almost every time the pressure slice p(t) has the square-integrable weak gradient
-(∂ₜu - Δu + (u·∇)u)(t).
Smooth compactly supported scalar functions on ℝ³, as a real vector space
(prop:lps-smoothing).
Equations
- One or more equations did not get rendered due to their size.
Instances For
The data of a scalar test in slice identities: the test itself (index none) and its
first partial derivatives (index some k) (prop:lps-smoothing).
Equations
- One or more equations did not get rendered due to their size.
Instances For
The data of a scalar test are square integrable (prop:lps-smoothing).
Slice identities for a linear family of tests: if each identity holds for almost every
time and the slice data are square integrable for almost every time, then almost every time
satisfies all the identities simultaneously (prop:lps-smoothing).
prop:lps-smoothing: the pressure equation on almost every time slice. For almost every
time t, the pressure slice p(t) is square integrable and has the square-integrable weak
gradient Gq = -(∂ₜu - Δu + (u·∇)u)(t), where Δu = Σⱼ ∂ⱼ∂ⱼu and
((u·∇)u)ᵢ = Σⱼ uⱼ ∂ⱼuᵢ.