The spreading of corpse scent in water: Finding a submerged corpse with the help of fluidmechanical knowledge

The spreading of corpse scent in water: Finding a submerged corpse with the help of fluidmechanical knowledge

Bil, R.

Stelling, G.S. (mentor)
Uijttewaal, W.S.J. (mentor)
Van de Graaff, J. (mentor)
Wols, B. (mentor)

Civil Engineering and Geosciences

2008-06-20

A search for a victim of drowning is not always successful in practice: according to a rough guess only one out of ten corpses is found during a search by the authorities concerned. Several methods can be used in order to detect a corpse. In The Netherlands it is common to search with (tracker) dogs on the basis of corpse scent. Scent is detected at the water surface within a certain area; on the basis of this marking the corpse has to be detected at the bottom. However, flowing water and wind can spread and displace the scent (of a corpse) over considerable distances. The authorities concerned do not have expertise about these processes and are therefore unable to give a grounded indication of the location of the corpse. This is one of the reasons why so few searches are successful. Therefore, knowledge about the spreading and displacement of scent in water and air will be helpful in the search for victims of drowning. Objective The aim of the present study is to develop guidelines to determine the probable location of submerged corpses when a scent detector (usually a dog) is used above the water surface. The intended result of this study is to shorten the duration of the search and to reduce the number of unsuccessful operations. Findings A major finding of this study is the possibility to model the spreading and displacement of scent and its detection by dogs with a model which is based on the theory of mixing of a passive tracer. This is possible, despite the lack of knowledge about the aromatic substances and the fact that dogs (!) detect scent above (!) the water surface. On this basis, a guideline was developed that determines the location of a drowned victim in a straight and open channel with a stationary and uniform flow. The required information for this guideline regards the depth (of the water) and the largest distance between the several canine alerts; the velocity of the current is of no importance. The spreading and displacement of scent by complex flow structures have to be investigated by numerical simulations - every case again. The documentation of the real-life cases is poor, so conclusions about the validation of the presented results could hardly be drawn.

turbulence
submerged corpse
scent
guidelines

http://resolver.tudelft.nl/uuid:a32ec3f6-6020-45e8-be89-9f097dd661fc

TU Delft, Civil Engineering and Geosciences, Hydraulic Engineering

Student theses

master thesis

(c) 2008 R.Bil