BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Gravity current head formation and microbreaking in shallow water 
 dam break flows with friction - Gavin Esler (University College London)
DTSTART:20221206T140000Z
DTEND:20221206T143000Z
UID:TALK183806@talks.cam.ac.uk
DESCRIPTION:The study of dam break flows in the inviscid shallow water equ
 ations dates back to the similarity solution of Ritter (1892). A natural m
 odification to the problem\, considered by Whitham and others\, is to add 
 a frictional drag force in the momentum equation. At early times this fric
 tion affects Ritter's solution only in a small but expanding region near t
 he tip of the dam break flow. The solution in this region can be described
  by a further similarity theory\, developed by Hogg and Pritchard. Here we
  show that\, for drag laws commonly used in applications\, the Hogg-Pritch
 ard equations - which are known to exhibit critical behaviour - do not adm
 it continuous solutions and must be regularised by a rear-facing hydraulic
  jump or dispersive shock wave. The solutions therefore give - arguably - 
 the simplest mathematical account of the origin of the gravity current `he
 ad' seen in experiments. Interestingly\, if a dispersive shock wave is use
 d to regularise the Hogg-Pritchard equations it must be of a non-standard 
 type\, due to the dilation of the local coordinate system.&nbsp\;
LOCATION:Seminar Room 1\, Newton Institute
END:VEVENT
END:VCALENDAR