Adomian decomposition solution for propulsion of dissipative magnetic Jeffrey biofluid in a ciliated channel containing a porous medium with forced convection heat transfer

Physiological transport phenomena often feature ciliated internal walls. Heat, momentum and multi-species mass transfer may arise and additionally non-Newtonian biofluid characteristics are common in smaller vessels. Blood (containing hemoglobin) or other physiological fluids containing ionic constituents in the human body respond to magnetic body forces when subjected to external (extra-corporeal) magnetic fields. Inspired by such applications, in the present work we consider the forced convective flow of an electrically-conducting viscoelastic physiological fluid through a ciliated channel under the action of a transverse magnetic field. The flow is generated by a metachronal wave formed by the tips of cilia which move to and fro in a synchronized fashion. The presence of deposits (fats, cholesterol etc) in the channel is mimicked with a Darcy porous medium drag force model. The two-dimensional unsteady momentum equation and energy equation are simplified with a stream function and small Reynolds' number approximation. The effect of energy loss is simulated via the inclusion of viscous dissipation in the energy conservation (heat) equation. The non-dimensional, transformed moving boundary value problem is solved with appropriate wall conditions via the semi-numerical Adomian decomposition method (ADM). The velocity, temperature and pressure distribution are computed in the form of infinite series constructed by ADM and numerically evaluated in a symbolic software (MATHEMATICA). Streamline distributions are also presented. The influence of Hartmann number (magnetic parameter), Jeffrey first and second viscoelastic parameters, permeability parameter (modified Darcy number), and Brinkman number (viscous heating parameter) on velocity, temperature, pressure gradient and bolus dynamics is visualized graphically. The flow is decelerated with increasing with increasing Hartmann number and Jeffery first parameter in the core flow whereas it is accelerated in the vicinity of the walls. Increasing permeability and Jeffery second parameter are observed to accelerate the core flow and decelerate the peripheral flow near the ciliated walls. Increasing Hartmann number elevates pressure gradient whereas it is reduced with permeability parameter. Temperatures are elevated with increasing magnetic parameter, Brinkman number and Jeffery second parameter. Increasing magnetic field is also observed to reduce the quantity of trapped boluses. Increasing permeability parameter suppresses streamline amplitudes. Both the magnitude and quantity of trapped boluses is elevated with an increase in both first and second Jeffery parameters

Investigations of the Fundamentals of Passive Scalar Dynamics using Nano-sensing devices

Turbulence has been the core of numerous investigations over several decades. Among the wide spectrum of turbulence aspects, we focus on temperature as passive scalar advected in a turbulent velocity field. In this study, fundamental flow quantities are revisited by investigating statistically homogeneous and isotropic turbulence, with an imposed mean cross-stream linear temperature gradient. This is made possible by developing a new fast response nano-sensor to minimize measurement errors inherent in conventional temperature probes (cold wires). It is observed that cold wire attenuation has widespread effects on most aspects of themeasurements, resulting in the variance and the scalar rate of dissipation being significantly underestimated. Newly acquired data allow for a theoretical study of the temperature spectra, the dissipation range, different scaling laws and intermittencies. By studying the evolution equations of the temperature spectra, conditions for self-preserving solutions are derived and experimentally validated. Self-similarity of the dissipation subrange is explored,which reveals that the temperature field can be independently resolvedwithout knowledge of the velocity field. The results raise interesting questions about the underlying behavior of the scalar field, namely local equilibrium versus non-equilibrium. Based on the proposed scaling and the significant departure of existing models from the expected power-law behavior in the inertial range, a model spectrum is developed based entirely on temperature-related variables, showing a convincing agreement with the experimental data in the dissipation range. The underlying cause of scalar intermittencies, a well-established phenomenon reflected in the exponential tails of the scalar PDF, is yet to be determined. The interplay between advection and diffusion is investigated through their timescales ratio, following the linear eddymodel of Kerstein. The analysis reveals a widening iii of the PDF as more of the low frequency content is excluded. The development of the new sensor, along with the fundamental study, inspires new ideas for measuring conductivity as a way to assess humidity in the atmospheric boundary layer or blood damage due to shear stresses. Overall, the study sheds light on the importance of accurate and optimized measurement techniques in the pursuit of understanding turbulence

Glycaemic control and hypoglycaemia with insulin glargine 300U/mL versus insulin glargine 100U/mL in insulin-<em>na\uefve</em> people with type 2 diabetes: 12-month results from the EDITION 3 trial

Aerodynamic drag is the cause for more than two-thirds of the fuel consumption of large trucks at highway speeds. Due to functionality considerations, the aerodynamic efficiency of the aft-regions of large trucks was traditionally sacrificed. This leads to massively separated flow at the lee-side of truck-trailers, with an associated drag penalty of at least a third of the total aerodynamic drag. Active Flow Control (AFC), the capability to alter the flow behavior using unsteady, localized energy injection, can very effectively delay boundary layer separation. By attaching a compact and relatively inexpensive “add-on” AFC device to the back side of truck-trailers (or by modifying it when possible) the flow separating from it could be redirected to turn into the lee-side of the truck, increasing the back pressure, thus significantly reducing drag. A comprehensive and aggressive research plan that combines actuator development, computational fluid dynamics and bench-top as well as wind tunnel experiments was performed. The research uses an array of 15 newly developed Suction and Oscillatory Blowing actuators housed inside a circular cylinder attached to the aft edges of a generic 2D truck model. Preliminary results indicate a net drag reduction of 10% or more