The Dynamics of Blood Drop Release from Swinging Objects in the Creation of Cast-off Bloodstain Patterns†
Corresponding Author
Elisabeth M. P. Williams Ph.D.
Institute of Environmental Science and Research (ESR) Ltd, Christchurch Science Centre, PO Box 29-1818041, Christchurch, New Zealand
Department of Exercise Science, University of Auckland, Private Bag 92019, Auckland, 1142 New Zealand
Forensic Science, School of Chemical Sciences, University of Auckland, Private Bag 92019, Auckland, 1142 New Zealand
Applied Sports, Technology, Exercise and Medicine (A-STEM) Research Centre, College of Engineering, Swansea University, Swansea, SA18EN U. K.
Corresponding author: Elisabeth M. P. Williams, Ph.D. E-mail: [email protected]Search for more papers by this authorEmma S. Graham M.Sc.
Institute of Environmental Science and Research (ESR) Ltd, Christchurch Science Centre, PO Box 29-1818041, Christchurch, New Zealand
Search for more papers by this authorMark C. Jermy Ph.D.
Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch, 8041 New Zealand
Search for more papers by this authorDavid C. Kieser Ph.D., M.B.Ch.B.
Department of Orthopaedic Surgery and MSM, University of Otago, 2 Riccarton Avenue, Christchurch Central, Christchurch, 4710 New Zealand
Search for more papers by this authorMichael C. Taylor Ph.D.
Institute of Environmental Science and Research (ESR) Ltd, Christchurch Science Centre, PO Box 29-1818041, Christchurch, New Zealand
Search for more papers by this authorCorresponding Author
Elisabeth M. P. Williams Ph.D.
Institute of Environmental Science and Research (ESR) Ltd, Christchurch Science Centre, PO Box 29-1818041, Christchurch, New Zealand
Department of Exercise Science, University of Auckland, Private Bag 92019, Auckland, 1142 New Zealand
Forensic Science, School of Chemical Sciences, University of Auckland, Private Bag 92019, Auckland, 1142 New Zealand
Applied Sports, Technology, Exercise and Medicine (A-STEM) Research Centre, College of Engineering, Swansea University, Swansea, SA18EN U. K.
Corresponding author: Elisabeth M. P. Williams, Ph.D. E-mail: [email protected]Search for more papers by this authorEmma S. Graham M.Sc.
Institute of Environmental Science and Research (ESR) Ltd, Christchurch Science Centre, PO Box 29-1818041, Christchurch, New Zealand
Search for more papers by this authorMark C. Jermy Ph.D.
Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch, 8041 New Zealand
Search for more papers by this authorDavid C. Kieser Ph.D., M.B.Ch.B.
Department of Orthopaedic Surgery and MSM, University of Otago, 2 Riccarton Avenue, Christchurch Central, Christchurch, 4710 New Zealand
Search for more papers by this authorMichael C. Taylor Ph.D.
Institute of Environmental Science and Research (ESR) Ltd, Christchurch Science Centre, PO Box 29-1818041, Christchurch, New Zealand
Search for more papers by this authorAbstract
Although the characteristics of cast-off bloodstain patterns are well known, the physics of the mechanism by which they are created is poorly understood. The aim of this work was to describe the process by which blood droplets disengage from swinging objects. Cast-off droplets were recorded using high-speed digital video photography, and the resulting cast-off patterns were analyzed to draw inferences about the trajectories of individual drops. Blood on the object's distal end formed ligaments, which subsequently disintegrated into droplets. Initial droplet trajectories were approximately tangential to the trajectory of the location on the object from which the droplet was released. The application of the laws of physics to the mechanism of cast-off is discussed, and the process of drop formation is compared to that of passive drop formation. A technical description of cast-off is proposed, and a diagram to aid investigators in interpreting cast-off patterns at crime scenes is offered.
References
- 1Berlet AC, Talenti DP, Carroll SF. The baseball bat: a popular mechanism of urban injury. J Trauma 1992; 33(2): 167–70.
- 2Lightbody CJ, MacIver C. The baseball bat: a modern day cudgel. Emerg Med J 2007; 24(2): 112.
- 3Dujovny M, Onyekachi I, Perez-Arjona E. Baseball bats: a silent weapon. Neurol Res 2009; 31(10): 1005–11.
- 4 OSAC BPA. Terms and definitions in bloodstain pattern analysis. ASB Technical Report 033. Washington, DC: AAFS Standards Board, 2017.
- 5Bevel T, Gardner RM. Bloodstain pattern analysis with an introduction to crime acene reconstruction, 3rd edn. Boca Raton, FL: CRC Press, 2008.
- 6James SH, Kish PE, Sutton TP. Principles of bloodstain pattern analysis: theory and practice. Boca Raton, FL: CRC Press, Taylor and Francis Group, 2005.
10.1201/9781420039467 Google Scholar
- 7Wonder A. Blood dynamics. San Diego, CA: Academic Press, 2008.
- 8MacDonnell HL. Bloodstain patterns, 2nd edn. Corning, NY: Laboratory of Forensic Sciences, 2005.
- 9Raymond MA. Trajectory determination from bloodstains at a crime scene [PhD thesis]. Bundoora, Australia: La Trobe University, 1997.
- 10Ross E. The study of bloodstain patterns resulting from the release of blood drops from a weapon [Masters thesis in forensic science]. Auckland, New Zealand: University of Auckland, 2006.
- 11Williams EMP. From Weapon to wall: investigating the link between cast-off bloodstain patterns, blood dynamics and assailant kinematics [PhD thesis]. Auckland, New Zealand: University of Auckland, 2014.
- 12Williams E. The biomechanics of blunt force trauma [Masters thesis in forensic science]. Auckland, New Zealand: University of Auckland, 2008.
- 13Kunz SN, Adamec J, Grove C. Analyzing the dynamics and morphology of cast-off pattern at different speed levels using high-speed digital video imaging. J Forensic Sci 2017; 62(2): 428–34.
- 14Fischer WC. Utilizing bloodstains in accident reconstruction. In: H James, editor. Scientific and legal applications of bloodstain pattern interpretation. Boca Raton, FL: CRC Press, 1998.
- 15Bevel T, Gardner RM. Bloodstain pattern analysis with an introduction to crime scene reconstruction, 2nd edn. Boca Raton, FL: CRC Press, 2002.
- 16Liu H. Science and engineering of droplets: fundamentals and applications. William Norwich, NY: Andrew Publishing, 2000.
- 17Lavernia EJ, Yue W. Spray atomization and deposition. Irvine, CA: John Wiley & Sons, 1996.
- 18Kabaliuk N, Jermy MC, Williams EMP, Laber TL, Taylor MC. Experimental validation of a numerical model for predicting the trajectory of blood drops in typical crime scene conditions, including droplet deformation and breakup, with a study of the effect of indoor air currents and wind on typical spatter drop trajectories. Forensic Sci Int 2014; 245: 107–20.
- 19Attinger D, Moore C, Donandson A, Jafari A, Stone HA. Fluid dynamics topics in bloodstain pattern analysis: comparative review and research opportunities. Forensic Sci Int 2013; 231(1–3): 375–96.
- 20Kabaliuk N, Jermy MC, Morison K, Stotesbury T, Taylor MC, Williams EMP. Blood drop size in passive dripping from weapons. Forensic Sci Int 2013; 228(1–3): 75–82.
- 21Bunn JW. Scientific principles of coaching. Englewood Cliffs, NJ: Prentice-Hall Inc, 1972.
- 22Roach NT, Venkadesan M, Rainbow MJ, Lieberman DE. Elastic energy storage in the shoulder and the evolution of high-speed throwing in Homo. Nature 2013; 498(7455): 483–6.
- 23Welch CM, Banks SA, Cook FF, Draovitch P. Hitting a baseball: a biomechanical description. J Orthop Sports Phys Ther 1995; 22(5): 193–201.
- 24Escamilla RF, Fleisig GS, DeRenne C, Taylor MK, Moormanm CT, Imamura R, et al. A comparison of age level on baseball hitting kinematics. J Appl Biomech 2009; 25(3): 210–8.
- 25Putnam CA. Sequential motions of body segments in striking and throwing skills: descriptions and explanations. J Biomech 1993; 26(Suppl1): 125–35.
- 26Kibler WB, Wilkes T, Sciascia A. Mechanics and pathomechanics in the overhead athlete. Clin Sports Med 2013; 32(4): 637–51.
- 27Serway RA, Jewett JW. Physics for scientists and engineers, 8th edn. Pacific Grove, CA: Brooks Cole, 2009.
- 28Williams EMP, Taylor MC. Technical paper: the development and construction of a motorized blood droplet generation device (BDGD), for detailed analysis of blood droplet dynamics. J Bloodstain Pattern Anal 2013; 29(1): 14–29.
- 29Williams E, Neumann E, Taylor M. The development of a passive, closed-system pig blood collection apparatus for bloodstain pattern analysis research and crime scene reconstruction. Journal of Bloodstain Pattern Analysis 2012; 28(2): 11–8.
- 30Raymond MA, Smith ER, Liesegang J. The physical properties of blood – forensic considerations. Sci Justice 1996; 36(3): 153–60.
- 31Hulse-Smith L, Mehdizadeh NZ, Chandra S. Deducing drop size and impact velocity from circular bloodstains. J Forensic Sci 2005; 50(1): 54–63.
- 32Dong H, Carr WW, Morris JF. An experimental study of drop-on-demand drop formation. Phys Fluids 2006; 18(7): 072102.
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