Campus Units

Mechanical Engineering

Document Type

Article

Publication Version

Submitted Manuscript

Publication Date

2018

Abstract

The bloodstain pattern analyst sometimes has to judge if a given stain could originate from a specific location. A wide range of values of the maximum distance that a blood drop can travel have been reported from experiments, ranging from less than one meter to more than 10 meter. Here we formulate the problem in a fluid dynamics and big data framework. The fluid dynamics is solved with Newton’s classical equation of motion coupled with well‐established models for the gravity and drag forces that bend the trajectories of drops. The parameters screened are the drop size, initial velocity and launch angle, as well as the height of a blood source and the ceiling height. Combining a wide range of values of those five parameter commended the performance of more than 4.5 million fluid dynamic simulations. Results of those simulations have been searched and mined for additional parameters directly measurable on a crime scene, such as the stain size and stain ellipticity. The results are presented in simple charts. Those charts are easy to use, and do not require any knowledge of fluid dynamics from the analyst.

Comments

This manuscript based on presentation of D. Attinger at 1st "IABPA (International Association of Bloodstain Pattern Analysts) Congresso International de Analistas de Patrones de Manchas de Sangre," June 27-28, 2018, in Buenos Aires, Argentina. Presentation entitled "Determinacion de la distancia maxima de viaje de una gota de sangre" Posted with permission.

Copyright Owner

The Author

Language

en

File Format

application/pdf

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