{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"c6c6ab40a9724d97a00d4eaa2a677f6317cc3f790dc56722953e98a2cf06089f","created":"2026-10-03T07:18:03Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"4345e3fe365d08d15edfa4a338d0be43a6084200c6d835a4609a6bd8ba726c7b","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"identification","assisted_by":[],"external_id":"fluid.cavitation.erosion-load","kind":"well-posed","literature_status":"partially-resolved","n":"1","parents":[],"plain":"A bubble collapsing next to a metal surface fires a fast liquid jet into it and also sends out shock waves, and repeated collapses pit the metal. Which of these does the damage, and how does that depend on the bubble's distance from the wall?","posed_since":"","precise":"For a bubble of maximum radius $R_{\\mathrm{max}}$ collapsing at stand-off parameter $\\gamma = d/R_{\\mathrm{max}}$ from a rigid wall, determine the peak wall pressure, its duration and impulse from jet impact (jet speeds $\\sim 1e4\\,\\mathrm{cm/s}$ and above) versus the shock emitted at the collapse of the toroidal bubble, as functions of $\\gamma$, and which quantity correlates with measured pit formation in metals. An answer is a damage criterion in terms of $\\gamma$, $R_{\\mathrm{max}}$ and driving pressure that predicts pit depth and occurrence.","problem_ref":null,"references":"","settled_by":"Synchronized high-speed imaging, wall-pressure measurement and post-mortem pit analysis on metal targets over a scan of $\\gamma$, compared with compressible simulations of the same collapses.","status_note":"Work over the last decade points to the shock from toroidal collapse at intermediate stand-off and to thin, very fast jets at very small stand-off; no unified damage criterion as of 2026 (not re-verified for 2024-2026).","title":"Which collapse load, liquid jet or shock wave, causes cavitation erosion?","topic_ref":"ce084ca85ea118983bae60657d686bf2b3a2063cc2bba0a728c0b347e11c1da4"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"89247ed389a6f610f4f8fbf30fa5d4a3d598d54bccb72840620ed5950bf6da4a","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"8ebf7b89a6fe6031df4a319eb537732446603df0a1dbef70fd9ecec3148ebde5","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"_ym_ofXCscbv5uBw215qcQ9VCQPumCXG7QULPQVKd9mizw74f6CC2aWtgPOndh4bscSi2Kk4WEywl5M2LN4WBg"},"schema":"pubphys.envelope/1"},"record_hash":"89247ed389a6f610f4f8fbf30fa5d4a3d598d54bccb72840620ed5950bf6da4a","leaf_index":1395}