Errors in the estimation of the distance of fall and angles of impact blood drops

Willis, Cordelia; Piranian, Anna K.; Donaggio, John R.; Barnett, R.J.; Rowe, Walter F.

doi:10.1016/s0379-0738(01)00506-0

Cited by 34 publications

(23 citation statements)

References 1 publication

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“…(32) can be used as suggested by Garrison [4] to determine the angle of impact u from W and L. However, the uncertainty in the calculated angle of impact increases as the angle of impact approaches 908, as has been discussed by Willis et al [7] in connection with the calculation of the angles of impact of blood drops with target surfaces. The use of Eq.…”

Section: Discussionmentioning

confidence: 99%

The distribution of shotgun pellets after ricochet from an intermediate target surface

Rowe

2005

Forensic Science International

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Section: Discussionmentioning

confidence: 99%

The distribution of shotgun pellets after ricochet from an intermediate target surface

Rowe

2005

Forensic Science International

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“…This is probably realistic for substrates that are hydrophilic, but not for hydrophobic substrates, such as greasy tiles, where the stain diameter can be smaller than the maximum diameter reached during impact, as clearly shown in [42] 2) the stain diameter indicates the distance of fall [121], i.e. the impact velocity: this is only true if the initial size of the drop is known, as was also clearly shown in [42].…”

Section: Normal Impactmentioning

confidence: 96%

“…The error using the formula (10) is estimated in [89,121]. Note that elliptic stains do not necessarily imply an oblique impact, as any relative motion of the target perpendicular to the drop trajectory can cause a non-circularity in the observed stain, a fact studied experimentally in [123].…”

Section: Oblique Impactmentioning

confidence: 99%

Fluid dynamics topics in bloodstain pattern analysis: Comparative review and research opportunities

Attinger

Moore

Donaldson

et al. 2013

Forensic Science International

154

139

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This comparative review highlights the relationships between the disciplines of bloodstain pattern analysis (BPA) in forensics and that of fluid dynamics (FD) in the physical sciences. In both the BPA and FD communities, scientists study the motion and phase change of a liquid in contact with air, or with other liquids or solids. Five aspects of BPA related to FD are discussed: the physical forces driving the motion of blood as a fluid; the generation of the drops; their flight in the air; their impact on solid or liquid surfaces; and the production of stains. For each of these topics, the relevant literature from the BPA community and from the FD community is reviewed. Comments are provided on opportunities for joint BPA and FD research, and on the development of novel FD-based tools and methods for BPA. Also, the use of dimensionless numbers is proposed to inform BPA analyses. Keywordsbloodstain pattern analysis, review, dimensionless number, drop generation, trajectory, impact, stain Disciplines Laboratory and Basic Science Research | Other Mechanical EngineeringComments NOTICE: this is the author's version of a work that was accepted for publication in Forensic Science International. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Forensic Science International, [231, 1-3, (2013) Abstract: This comparative review highlights the relationships between the disciplines of bloodstain pattern analysis (BPA) in forensics and that of fluid dynamics (FD) in the physical sciences. In both the BPA and FD communities, scientists study the motion and phase change of a liquid in contact with air, or with other liquids or solids. Five aspects of BPA related to FD are discussed: the physical forces driving the motion of blood as a fluid; the generation of the drops; their flight in the air; their impact on solid or liquid surfaces; and the production of stains. For each of these topics, the relevant literature from the BPA community and from the FD community is reviewed. Comments are provided on opportunities for joint BPA and FD research, and on the development of novel FD-based tools and methods for BPA. Also, the use of dimensionless numbers is proposed to inform BPA analyses.

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“…Willis et al [4] have shown that the uncertainty in the calculated angle of impact of a blood drop is a function of the angle of impact itself. For example, the angle b L is calculated from the width W L and length L L of the bloodstain at point O in Fig.…”

Section: Effect Of Variation In the Uncertainties Of The Angles Of Immentioning

confidence: 99%

“…(11) depends on the following assumptions (which underlie the use of the Balthazard formula): the drop of blood is spherical at the time of impact and has travelled in a straight line to the point of impact. Willis et al [4] showed that the variance in the angle of impact can be calculated accurately from the variances in the width and the length measurements. This shows that the uncertainties in the angles of impact are determined primarily by the uncertainties in the width and length measurements.…”

Section: Effect Of Variation In the Uncertainties Of The Angles Of Immentioning

confidence: 99%

Errors in the determination of the point of origin of bloodstains

Rowe

2006

Forensic Science International

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Errors in the estimation of the distance of fall and angles of impact blood drops

Cited by 34 publications

References 1 publication

The distribution of shotgun pellets after ricochet from an intermediate target surface

The distribution of shotgun pellets after ricochet from an intermediate target surface

Fluid dynamics topics in bloodstain pattern analysis: Comparative review and research opportunities

Errors in the determination of the point of origin of bloodstains

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