Documentation

LeanPool.NavierStokesAndEuler.NavierStokes.R3.PressureFlux

Canonical pressure flux #

The pressure is paired with compact smooth tests through its canonical Riesz functional. Every integral used to split the weighted pairing is shown to be integrable before its norm is estimated.

Compact time tests of the conservative pressure identity #

The temporal test has topological support inside the open time interval. The spatial test is smooth and compactly supported. Consequently all pairings are ordinary Lebesgue integrals even when the pressure grows at spatial infinity.

Compact tests used in pressure recovery #

Real compact smooth tests are embedded in the actual complex Schwartz space. The differential operators commute with this embedding. The pressure identities below continue to pair the physical pressure only with compact spatial tests.

Weak time continuity from uniform spatial bounds #

A jointly continuous scalar field with uniformly bounded spatial norm has continuous pairings with every continuous test vanishing at infinity. Only the test is approximated by compactly supported functions; no support or derivative bound is imposed on the field.

Pressure recovery for smooth finite-energy comparisons #

The physical pressure is tested only against compact smooth functions. Its canonical representative is recovered from the conservative equation, time averaging, and the vanishing theorem for harmonic Sobolev-bounded functionals.

Time averages of finite-energy fields #

These averages use the ordinary Bochner integral on a finite closed time interval. Their spatial integrability follows from joint continuity and the uniform spatial integral bounds; no time derivative or global spatial derivative bound is used.

Pointwise recovery from compact temporal tests #

The compact test function in the pressure flux #

The identity φ² r = D(φ⁸)[w] places the localized pressure flux in the commutator form. Its estimates use only the unweighted velocity energy and the weighted velocity and gradient norms.

The actual pressure flux equals the canonical pressure flux #

The scalar gradient identification is supplied by the proved pressure recovery theorem. The only compact support in this identity is that of the cutoff.

From scalar pressure-gradient identification to the cutoff pressure flux #

This module is an integration-by-parts bridge. Its input is an explicit identification of every compact scalar pressure-gradient pairing. It does not assume a pressure-flux formula or any bound on the pressure at infinity.

Weighted tensor bounds for the localized pressure #

The tensor difference is expanded around the reference velocity. Its two cross terms use of that velocity and of the difference; the quadratic term uses the cutoff interpolation estimate. All norms remain finite explicitly.