{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"54f752cdb3a7de87676bf17d41b355d251b787a7f75668333f26e35dd4edab4c","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["1f92cb59a4301690c7f67503ca32dbeca842b8a898e90eb456d0a98181b4cae3","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"b3778bfaaec28e584098e7ad9612c05d26fc1afa2ebc9558123c14c9840976af","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":"2","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 $R/\\delta_L >\\sim 10^{4}$, 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":"1f92cb59a4301690c7f67503ca32dbeca842b8a898e90eb456d0a98181b4cae3","references":"","settled_by":"Large-scale simulations or large-volume experiments that reach $R/\\delta_{L}$ of $10^{4}$ 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":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"46ea1c5be83e9aad5999f58f8d43f7ab3c86cecd9a2e393fd8780d5fd5301453","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"5211077b09f355f3008bb9c6ef17845141d4dbcbf65820ac606985560791ea15","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"5Jh1za_1Zd2Qzyl7URl_TfP1cTX-WTZ-ih4PSDImWbiqubqedOHOQ0qCpwOK_RDkwqb8KaVR8bQwy0JuO-vrAQ"},"schema":"pubphys.envelope/1"},"record_hash":"46ea1c5be83e9aad5999f58f8d43f7ab3c86cecd9a2e393fd8780d5fd5301453","leaf_index":3286}