{ "id": "1708.09360", "version": "v1", "published": "2017-08-30T16:49:33.000Z", "updated": "2017-08-30T16:49:33.000Z", "title": "Finite time blow up for a fluid mechanics model with nonlocal velocity", "authors": [ "Changhui Tan" ], "comment": "14 pages", "categories": [ "math.AP" ], "abstract": "We study a 1D fluid mechanics model with nonlocal velocity. The equation can be viewed as a fractional porous medium flow, a 1D model of the quasi-geostrophic equation, and also a special case of Euler-Alignment system. For strictly positive smooth initial data, global regularity has been proved by Do, Kiselev, Ryzhik and Tan. We construct a family of non-negative smooth initial data so that solution loses regularity in finite time. Our result indicates that strict positivity is a critical condition to ensure global regularity of the system. We also extend our construction to the corresponding models in multi-dimensions.", "revisions": [ { "version": "v1", "updated": "2017-08-30T16:49:33.000Z" } ], "analyses": { "subjects": [ "35Q35", "35Q92" ], "keywords": [ "finite time blow", "nonlocal velocity", "positive smooth initial data", "1d fluid mechanics model", "global regularity" ], "note": { "typesetting": "TeX", "pages": 14, "language": "en", "license": "arXiv", "status": "editable" } } }