Bloodstain pattern analysis is of tremendous value for the investigation of the evidence at the crime scene. Analyzing the bloodstain patterns provides an appropriate method for retracing the origin of blood droplets and also reconstruction of the crime scene. The patterns of the bloodstains on the floors and walls are determined by the impact conditions of blood drops such as droplet sizes, impact angles and velocities. The objective of this work is to study the bloodstain patterns on an inclined surface, in order to categorize the bloodstain shapes. The experiments have been carried out using a 38% glycerol solution at room temperature between 16° C∼21° C. The experiments have been done for three different droplet diameters, five different velocities and four different surface inclinations. The blood-mimicking fluid viscosity and density have been measured at the same temperature range with the experiments. The results have been investigated in terms of bloodstain shape and patterns and three different categories have been determined. In addition, a new mathematical formula has been derived based on the equivalent diameter of the bloodstains, which relates the bloodstain dimensions to the droplet Reynolds and Weber numbers. It has been shown that the proposed formula fits more accurately with the experimental results for high impact angle cases as compared to the classical formula.
- Fluids Engineering Division
Analysis of Bloodstains Patterns at Sharp Impact Angles
Moshfeghi, M, Rahimipetroudi, I, & Hur, N. "Analysis of Bloodstains Patterns at Sharp Impact Angles." Proceedings of the ASME 2016 Fluids Engineering Division Summer Meeting collocated with the ASME 2016 Heat Transfer Summer Conference and the ASME 2016 14th International Conference on Nanochannels, Microchannels, and Minichannels. Volume 1B, Symposia: Fluid Mechanics (Fundamental Issues and Perspectives; Industrial and Environmental Applications); Multiphase Flow and Systems (Multiscale Methods; Noninvasive Measurements; Numerical Methods; Heat Transfer; Performance); Transport Phenomena (Clean Energy; Mixing; Manufacturing and Materials Processing); Turbulent Flows — Issues and Perspectives; Algorithms and Applications for High Performance CFD Computation; Fluid Power; Fluid Dynamics of Wind Energy; Marine Hydrodynamics. Washington, DC, USA. July 10–14, 2016. V01BT21A002. ASME. https://doi.org/10.1115/FEDSM2016-7862
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