The receding-axis zoom #
The recentred zoom-in map of eq:aniso:zoom:receding:variables sends ((R, Z), τ) to the
point with radius rc + lam * R, height zc + lam ^ (1 - 2 * h) * Z and parabolic time
lam ^ 2 * τ. Only the radial slot differs from eq:aniso:zoom:finite:variables, and it
differs by the constant offset rc, so every derivative in the recentred variables has
exactly the same prefactor as in the finite-axis variables.
The file follows CIV.Zoom.Rescaling, CIV.Zoom.ChainRule, CIV.Zoom.ChainRuleSecond,
CIV.Zoom.DivergenceIdentity and CIV.Zoom.RescaledBounds step by step; the receding
declarations carry a Rec suffix so that the two families never clash. The
second-derivative helpers are obtained from the general scalar chain rule of
CIV.Zoom.ScalarChainRule, which is stated for an arbitrary curve inside a fixed time
slice and therefore accepts the offset radial line of the recentred map.
The recentred zoom map and the rescaled fields #
V_n of eq:aniso:zoom:fields in the recentred variables.
Equations
- CIV.zoomVRec lam h rc zc u p = lam * u (CIV.zoomPointRec lam h rc zc p) 0
Instances For
W_n of eq:aniso:zoom:fields in the recentred variables.
Equations
- CIV.zoomWRec lam h rc zc u p = lam * lam ^ (2 * h) * u (CIV.zoomPointRec lam h rc zc p) 2
Instances For
S_n of eq:aniso:zoom:fields in the recentred variables.
Equations
- CIV.zoomSRec lam h rc zc u p = lam * lam ^ (2 * h) * u (CIV.zoomPointRec lam h rc zc p) 1
Instances For
The rescaled azimuthal vorticity Θ_n = lam² δ_n ω_θ of
eq:aniso:zoom:receding:vorticity.
Equations
- CIV.zoomTheta lam h rc zc u p = lam ^ 2 * lam ^ (2 * h) * CIV.azimuthalVorticity u (CIV.zoomPointRec lam h rc zc p)
Instances For
Membership, continuity and smoothness of the recentred zoom map #
zoomPointRec is affine in p, hence continuous. As in continuous_zoomPoint, the
codomain is named Y := Vec3 × ℝ so that the product topology, not the parabolic metric of
ParabolicPoint, is the one used (design note R2).
zoomPointRec is affine, hence smooth; the codomain is named F := Vec3 × ℝ for the
same reason as in continuous_zoomPointRec.
Derivatives of the recentred meridional line #
Moving the radial coordinate of a meridional point away from the offset b at speed a
moves it along e₁.
The recentred zoom map differentiated in R and in Z #
Differentiating a component of u ∘ zoomPointRec in the radial variable.
Differentiating a component of u ∘ zoomPointRec in the vertical variable.
First-order chain rules for the recentred fields #
∂_R V_n in terms of the radial partial derivative of u_r.
∂_Z V_n in terms of the vertical partial derivative of u_r.
∂_R W_n in terms of the radial partial derivative of u_z.
∂_Z W_n in terms of the vertical partial derivative of u_z.
∂_R S_n in terms of the radial partial derivative of u_θ.
∂_Z S_n in terms of the vertical partial derivative of u_θ.
Open-neighbourhood lemmas for the recentred zoom #
A first-order identity valid at every recentred zoom point of the unit cylinder holds on a
whole neighbourhood of p.1.1 inside the radial slice through p.
The vertical counterpart of eventuallyEq_slice_r_rec.
Second-derivative helpers for the recentred zoom #
The R-derivative of spatialPartial (u· i) 0 composed with zoomPointRec.
The R-derivative of spatialPartial (u· i) 2 composed with zoomPointRec.
The Z-derivative of spatialPartial (u· i) 2 composed with zoomPointRec.
Second-order chain rules for the recentred fields #
The rescaled azimuthal vorticity #
eq:aniso:zoom:receding:vorticity: the rescaled azimuthal vorticity is
Θ_n = δ_n² ∂_Z V_n - ∂_R W_n, with δ_n = lam ^ (2 * h).
The recentred divergence identity #
Off the receding axis, the recentred radial velocity divided by A + R equals lam²
times the meridional radial quotient at the recentred zoom point, with A = rc / lam.
eq:aniso:zoom:receding:div: in the recentred variables the divergence-free condition
reads ∂_R V_n + V_n / (A + R) + ∂_Z W_n = 0, with A = rc / lam, at every point with
R ≠ -A.
The anisotropic bounds in the recentred variables (eq:aniso:zoom:derivatives) #
The bound on the rescaled azimuthal vorticity #
eq:aniso:zoom:receding:bound: with δ_n = lam ^ (2 * h) the rescaled azimuthal
vorticity obeys |Θ_n| ≤ C (δ_n² |τ| ^ (-1 + h) + |τ| ^ (-1 - h)), the two terms coming
from the ∂_Z V_n and ∂_R W_n entries of eq:aniso:zoom:derivatives.