Anti-PIV type 3 Hemagglutinin Monoclonal antibody, Clone C3468M

Microfluidic platforms have increasingly been explored for in vitro blood diagnostics and for studying complex microvascular processes. The perfusion of blood in such devices is typically achieved through pressure-driven setups. Surface tension driven blood flow provides an alternative flow delivery option, and various studies in the literature have examined the behavior of blood flow in such fluidic devices. In such flows, the influence of red blood cell (RBC) aggregation, the phenomenon majorly responsible for the non-Newtonian nature of blood, requires particular attention. In the present work, we examine differences in the surface tension driven flow of aggregating and non-aggregating RBC and Newtonian suspensions, in a rectangular microchannel. The velocity fields were obtained using micro-PIV techniques. The analytical solution for blood velocity in the channel is developed utilizing the power law model for blood viscosity. The results showed that RBC aggregation has an impact at the late stages of the flow, observed mainly in the bluntness of the velocity profiles. At the initial stages of the flow, the shearing conditions are found moderately elevated, preventing intense RBC aggregate formation. As the flow decelerates in the channel, RBC aggregation increases, affecting the flow characteristics.

The influence of coherent turbulent structures on the entrainment characteristics of a separated shear layer in a Mach-2.49 longitudinal cylinder wake is investigated using stereoscopic particle image velocimetry (SPIV). Three thousand non-time-correlated velocity field measurements, acquired along a plane coincident with the central axis, were decomposed into modes using the snapshot proper orthogonal decomposition (POD) method. The second and third POD modes identified high-energy velocity fluctuations aligned with consistent directions in the separated shear layers, near the boundaries of the recirculation region. Previous work by the authors has demonstrated, using tomographic PIV, that these directionally consistent velocity fluctuations identified by the POD modes are caused by three-dimensional (3D) coherent upright and inverted hairpin vortex structures in this flow. The SPIV velocity field snapshots were conditionally sorted based on the value of their corresponding POD amplitude coefficients, and conditional statistics from these subsets of snapshots were used to derive results in the current work. It is demonstrated that a higher statistical prevalence of upright hairpin vortices in the shear layer directly correlates with reduced shear layer growth rates, and a subsequent increase in the reattachment length. Conversely, a higher statistical prevalence of inverted hairpin vortices correlates with increased shear layer growth rates, and a subsequent reduction in the reattachment length. Comparisons of conditional statistics for the SPIV data are drawn with previous laser Doppler velocimetry measurements acquired in a 5 degrees boat-tailed cylinder configuration of this flow. These comparisons demonstrate clear similarities of important features between the two flows, such as an increase in the reattachment length when compared to the unconditional blunt-based cylinder flow, which is indicative of higher cylinder base pressures and subsequently reduced pressure drag.