Forensic fluid dynamics: Insights into science of flow

Applying fluid dynamics to ink analysis in forensic context is explored in this research paper. The fluid dynamics of ink absorption and spread is a complex process that includes various physical and chemical processes. Stereomicroscopy is used in this study to examine the spread of ink in both paper and cloth. Inks of different consistency are used in two surfaces i.e., paper surface and cloth surface. The flow of ink is analyzed using a capillary tube to study the hydrodynamics of ink. Different physical characteristics like adhesion, surface tension, and viscosity play a key role in how ink transfers from a pen to paper. Capillary action allows liquids to move through narrow channels, defying gravity, and this is caused due to these three main factors. We have also implied Jurin's law and diffusion equation to arithmetically explain the spread of ink in two different surfaces. In conclusion, this study gives new insight for identifying the dispersion of ink and capillary action of ink to study the flow of ink. The ink trails reveal the flow of ink and the degree to which ink seeps into the paper can suggest whether a strong pressure was used, which may raise suspicions of forgery. The pressure exerted while writing can offer insights into the type of pen used and the writer's emotional and physical condition. For instance, heavier pressure might indicate more aggressive writing or a forced writing. All these observations in questioned documents will help in identifying the original and the fake.