advection_duo
This page is auto-generated from the rule's JSON by
tools/render_doc_plots.py. The discrete operator below is pretty-printed directly from the rule's replacement AST using EarthSciSerialization (earthsci_toolkit). Rules with a hand-authored page carry richer prose plus stencil and convergence diagrams; see the curated entries linked from the rule index.Pattern
Matches the §4.2 operator div on the pattern div({'op': '*', 'args': ['$U', '$q']}), dim=cell for grid family unstructured.
Discrete operator
Pretty-printed from the rule’s replacement AST ($-prefixed names are pattern variables bound by applies_to; grid metrics such as dx/dz are resolved by the grid):
out = Σ[k ∈ [1, 3]] ( index(edge_sign_on_face, i, k)·index(dc_edge, index(edges_on_face, i, k))/index(tri_area, i)·index($U, index(edges_on_face, i, k))·0.5·(index($q, i) + index($q, index(cell_neighbors, i, k))) )