Tracking blood drops ejected from the nasal cavity during violent assault

P. H. Geoghegan; C. J.T. Spence; N. Kabaliuk; J. Aplin; J. Wilhelm; M. C. Taylor; Mark C. Jermy

Tracking blood drops ejected from the nasal cavity during violent assault

P. H. Geoghegan^*
, C. J.T. Spence
, N. Kabaliuk
, J. Aplin
, J. Wilhelm
, M. C. Taylor
, Mark C. Jermy

^*Corresponding author for this work

Department of Mechanical Engineering
University of Canterbury
Fisher and Paykel Healthcare Limited
Institute of Environmental Science and Research (ESR)

Research output: Chapter in Book/Published conference output › Conference publication

Abstract

Expirated blood is blood released from the mouth or nose which leaves characteristic stains at crime scenes which may convey valuable information about the disposition of assailant and victim. Little work has been done to determine the typical velocities and trajectories of the droplets which make such patterns. Stereoscopic Particle Image Velocimetry (SPIV) and a model of the human upper airway were used to measure the velocity field near the nostrils during exhalation. The trajectories of blood drops emerging from the nose were computed with a numerical model. For an expiration flow rate of 32 l/min in vivo there is a maximum exit velocity from the nostril of approximately 4 m/s. From a height of 1.7 m blood drops between 0.5 mm and 2 mm reach terminal velocity. Their exit velocity at the nostril does not affect impact velocity, but it does influence impact location. Drop size affects both impact location and impact velocity. Compared to the 2 mm drop, the 0.5 mm drop had a reduced impact velocity, but its impact location in the ground plane was further from the nostril exit. Understanding the physics of expirated blood flight allows better interpretation of expirated stains on different surfaces at crime scenes.

Original language	English
Title of host publication	Proceedings of the 19th Australasian Fluid Mechanics Conference, AFMC 2014
ISBN (Electronic)	9780646596952
Publication status	Published - 2014
Event	19th Australasian Fluid Mechanics Conference, AFMC 2014 - Melbourne, Australia Duration: 8 Dec 2014 → 11 Dec 2014

Conference

Conference	19th Australasian Fluid Mechanics Conference, AFMC 2014
Country/Territory	Australia
City	Melbourne
Period	8/12/14 → 11/12/14

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 16 Peace, Justice and Strong Institutions

Cite this

@inproceedings{e2db01e930b04e828ea0f4b3da3ec0ce,

title = "Tracking blood drops ejected from the nasal cavity during violent assault",

abstract = "Expirated blood is blood released from the mouth or nose which leaves characteristic stains at crime scenes which may convey valuable information about the disposition of assailant and victim. Little work has been done to determine the typical velocities and trajectories of the droplets which make such patterns. Stereoscopic Particle Image Velocimetry (SPIV) and a model of the human upper airway were used to measure the velocity field near the nostrils during exhalation. The trajectories of blood drops emerging from the nose were computed with a numerical model. For an expiration flow rate of 32 l/min in vivo there is a maximum exit velocity from the nostril of approximately 4 m/s. From a height of 1.7 m blood drops between 0.5 mm and 2 mm reach terminal velocity. Their exit velocity at the nostril does not affect impact velocity, but it does influence impact location. Drop size affects both impact location and impact velocity. Compared to the 2 mm drop, the 0.5 mm drop had a reduced impact velocity, but its impact location in the ground plane was further from the nostril exit. Understanding the physics of expirated blood flight allows better interpretation of expirated stains on different surfaces at crime scenes.",

author = "Geoghegan, \{P. H.\} and Spence, \{C. J.T.\} and N. Kabaliuk and J. Aplin and J. Wilhelm and Taylor, \{M. C.\} and Jermy, \{Mark C.\}",

year = "2014",

language = "English",

booktitle = "Proceedings of the 19th Australasian Fluid Mechanics Conference, AFMC 2014",

note = "19th Australasian Fluid Mechanics Conference, AFMC 2014 ; Conference date: 08-12-2014 Through 11-12-2014",

}

TY - GEN

T1 - Tracking blood drops ejected from the nasal cavity during violent assault

AU - Geoghegan, P. H.

AU - Spence, C. J.T.

AU - Kabaliuk, N.

AU - Aplin, J.

AU - Wilhelm, J.

AU - Taylor, M. C.

AU - Jermy, Mark C.

PY - 2014

Y1 - 2014

N2 - Expirated blood is blood released from the mouth or nose which leaves characteristic stains at crime scenes which may convey valuable information about the disposition of assailant and victim. Little work has been done to determine the typical velocities and trajectories of the droplets which make such patterns. Stereoscopic Particle Image Velocimetry (SPIV) and a model of the human upper airway were used to measure the velocity field near the nostrils during exhalation. The trajectories of blood drops emerging from the nose were computed with a numerical model. For an expiration flow rate of 32 l/min in vivo there is a maximum exit velocity from the nostril of approximately 4 m/s. From a height of 1.7 m blood drops between 0.5 mm and 2 mm reach terminal velocity. Their exit velocity at the nostril does not affect impact velocity, but it does influence impact location. Drop size affects both impact location and impact velocity. Compared to the 2 mm drop, the 0.5 mm drop had a reduced impact velocity, but its impact location in the ground plane was further from the nostril exit. Understanding the physics of expirated blood flight allows better interpretation of expirated stains on different surfaces at crime scenes.

AB - Expirated blood is blood released from the mouth or nose which leaves characteristic stains at crime scenes which may convey valuable information about the disposition of assailant and victim. Little work has been done to determine the typical velocities and trajectories of the droplets which make such patterns. Stereoscopic Particle Image Velocimetry (SPIV) and a model of the human upper airway were used to measure the velocity field near the nostrils during exhalation. The trajectories of blood drops emerging from the nose were computed with a numerical model. For an expiration flow rate of 32 l/min in vivo there is a maximum exit velocity from the nostril of approximately 4 m/s. From a height of 1.7 m blood drops between 0.5 mm and 2 mm reach terminal velocity. Their exit velocity at the nostril does not affect impact velocity, but it does influence impact location. Drop size affects both impact location and impact velocity. Compared to the 2 mm drop, the 0.5 mm drop had a reduced impact velocity, but its impact location in the ground plane was further from the nostril exit. Understanding the physics of expirated blood flight allows better interpretation of expirated stains on different surfaces at crime scenes.

UR - https://www.scopus.com/pages/publications/84959096842

M3 - Conference publication

AN - SCOPUS:84959096842

BT - Proceedings of the 19th Australasian Fluid Mechanics Conference, AFMC 2014

T2 - 19th Australasian Fluid Mechanics Conference, AFMC 2014

Y2 - 8 December 2014 through 11 December 2014

ER -

Tracking blood drops ejected from the nasal cavity during violent assault

Abstract

Conference

UN SDGs

Other files and links

Fingerprint

Experimental measurement of breath exit velocity and expirated bloodstain patterns produced under different exhalation mechanisms

Experimental and computational investigation of the trajectories of blood drops ejected from the nose

Visualization of the air ejected from the temporary cavity in brain and tissue simulants during gunshot wounding

Cite this