{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"a7635f6f445cce75f1b6c2250b765524f809c489840c116cc1a5b64f265890e7","created":"2026-10-03T07:18:04Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"808002fff12210d25d437869dd5d5a4db12b0679bac82c5ff73e011f9b7af123","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"value","assisted_by":[],"external_id":"fluid.turbulent-combustion.self-acceleration-exponent","kind":"well-posed","literature_status":"contested","n":"1","parents":[],"plain":"A large spherical flame wrinkles by itself because the hot burned gas expands, and its radius then grows faster than steadily in time. Does this growth settle into a universal power law, and with what exponent?","posed_since":"","precise":"For an outwardly propagating premixed flame subject to the Darrieus-Landau (gas-expansion) and thermo-diffusive instabilities, determine whether the radius approaches a self-similar law $R \\sim t^{\\alpha}$ at $R/\\delta_L >\\sim 1e4$, the value of $\\alpha$ (field-scale correlations suggest $\\alpha = 3/2$, equivalent to a fractal front dimension $7/3$), and its dependence on expansion ratio and Lewis number. An answer is $\\alpha$ with uncertainty from simulations or experiments reaching the asymptotic range.","problem_ref":null,"references":"","settled_by":"Large-scale simulations or large-volume experiments that reach $R/\\delta_{L}$ of 1e4 or more and show a converged power law in $R(t)$.","status_note":"","title":"Asymptotic acceleration exponent of large self-wrinkling expanding flames","topic_ref":"ff8822779d7d3829d62f794eaee78060074a7c7c5588960c0eae974a587339ac"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"1f92cb59a4301690c7f67503ca32dbeca842b8a898e90eb456d0a98181b4cae3","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"39bc3c9812392bfa1616ce05b00e1777e81a5199a746bf4066c55a7ef4edaf56","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"DrGmJ_j2MdpqOgc7gii2CfrMPnq07AQWB2NF_pkv5y6Z6-fJkSv_sV56iaVrJN_Jp7OjqowJeIe49JTLzztNCQ"},"schema":"pubphys.envelope/1"},"record_hash":"1f92cb59a4301690c7f67503ca32dbeca842b8a898e90eb456d0a98181b4cae3","leaf_index":1449}