title: Three physical factors that affect the crown growth of the impact mechanism and its implications for bloodstain pattern analysis.
abstract: This research uses high-speed video analysis of bloodstain impact events to investigate the influence of impact velocity, fluid depth and free-space on the characteristics of the mechanism. We focus on the changes in the crown growth over time. This work demonstrates qualitative differences in the impact mechanism under a range of impact conditions. These differences are further explained quantitatively as a function of measured crown width and height lengths over time. Fluid dynamic explanations of this growth are featured in the results and discussion. A comparison to water dynamics is reported. Our image analysis demonstrates that droplets are consistently formed at points which are different from the impactor/fluid interface and that this difference is fluid dependent. This fluid dependency demonstrates the importance of accurately modeling fluid dynamics of blood when designing and deploying blood substitutes in forensics applications.
authors.affiliation: Trent University, 1600 West Bank Drive, Peterborough, Ontario K9J 7B8, Canada.
authors.forename: Theresa
authors.initials: T
authors.lastname: Stotesbury
authors.affiliation: Trent University, 1600 West Bank Drive, Peterborough, Ontario K9J 7B8, Canada.
authors.forename: Mike
authors.initials: M
authors.lastname: Illes
authors.affiliation: Department of Mechanical Engineering, University of Canterbury, 20 Kirkwood Ave, 8140 Christchurch, New Zealand.
authors.forename: Mark
authors.initials: M
authors.lastname: Jermy
authors.affiliation: The Institute of Environmental Science and Research, 27 Creyke Road, 8140 Christchurch, New Zealand.
authors.forename: Michael
authors.initials: M
authors.lastname: Taylor
authors.affiliation: Universiteit van Amsterdam, Spui 21, 1012 Amsterdam, The Netherlands.
authors.forename: Julie
authors.initials: J
authors.lastname: Wilhelm
authors.affiliation: Trent University, 1600 West Bank Drive, Peterborough, Ontario K9J 7B8, Canada. Electronic address: avreugdenhil@trentu.ca.
authors.forename: Andrew
authors.initials: A
authors.lastname: Vreugdenhil
mesh_terms: D001801:Blood Stains; D005554:Forensic Medicine / Q000592:standards*; D006801:Humans; D057446:Hydrodynamics
keywords: Bloodstain pattern analysis; Crown formation; Forensic science; High-speed video; Impact bloodstain pattern; Impact mechanism