2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/58048We propose a method of construction of exact solutions of free boundary problems corresponding to Hele-Shaw flows in presence of an external field. Such a field may arise, in particular, due to electrokinetic phenomena. Both a general approach and a number of examples are presented.26 pages, pdfMathematical PhysicsDynamical Systemstext