

Sinking Ship Vortex Equations
Name: Joyce
Status: student
Grade: 912
Location: PA
Country: USA
Date: Summer 2012
Question:
I see that there are questions pertaining to the mythical "sinking ship vortex" however, I was wondering how it could be proved mathematically that a vortex would not be created. Everywhere I search is either a definite yes or no, but there are no mathematics to support their claims.
Replies:
Hi Joyce,
There is no simple mathematical answer to how a fluid will respond to
a ship sinking. It depends on the nature of the ship and how it sinks.
The water and the ship will follow the laws of physics (for the math,
look up "continuity equations for fluids"), but exactly what happens
depends on the details of the situation. The challenge with a
turbulent system is even greater, as turbulence remains difficult to
model analytically.
You specifically ask about a 'vortex'  which is a special case of
turbulent flow. A sinking ship "could" create a vortex, but that does
not mean that *any* sinking ship "must" create a vortex. Again, it
depends on the situation.
If you are really interested in this topic, I suggest you read into
fluid dynamics, and specifically about secondary flows and, for
mathematics of fluids, start with the continuity equations for fluids.
I should warn you, this is graduatelevel (e.g. PhDstudents) content
 not for the faint of heart (or scaredofmath)!
Hope this helps,
Burr Zimmerman
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Update: November 2011

