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Roughness Influence on Human Blood Drop Spreading and Splashing.
Fiona R Smith1, Naomi C Buntsma1, David Brutin1
1Aix Marseille Université , CNRS, IUSTI, Marseille, France.
Langmuir : the ACS Journal of Surfaces and Colloids
|October 28, 2017
Summary
Surface roughness significantly impacts blood droplet splashing during crime scene analysis. This study reveals roughness is more critical than wettability in determining bloodstain patterns, aiding forensic investigations.
Area of Science:
- Forensic Science
- Fluid Dynamics
- Materials Science
Background:
- Bloodstain pattern analysis (BPA) is crucial for crime scene reconstruction.
- Existing research on droplet impact often overlooks non-Newtonian fluids like blood.
- The influence of surface properties on blood droplet behavior requires further investigation.
Purpose of the Study:
- To investigate how surface roughness and wettability affect the splashing limit of blood droplets.
- To understand the role of these surface properties in bloodstain pattern formation.
- To develop empirical solutions for predicting blood droplet impact outcomes.
Main Methods:
- High-speed camera recording of blood droplets impacting various surfaces at different velocities.
- Analysis of droplet impact recordings and surface characteristics (roughness, wettability).
- Comparison of the influence of roughness versus wettability on splashing behavior.
Main Results:
- Surface roughness was found to be a major factor in the splashing/non-splashing threshold of blood droplets.
- Wettability had a lesser impact on the splashing limit compared to roughness.
- Surface roughness was observed to alter the deformation characteristics of blood drip stains.
Conclusions:
- Surface roughness is a critical parameter in determining blood droplet impact outcomes in forensic analysis.
- Understanding the interplay between surface roughness and blood droplet dynamics enhances the interpretation of BPA evidence.
- These findings contribute to more accurate crime scene reconstruction by characterizing drip stains based on impact conditions.
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