Lattice Boltzmann model of percutaneous drug absorption

A lattice Boltzmann numerical modeling method was developed to predict skin concentration after topical application of a drug on the skin. The method is based on D2Q9 lattice spaces associated with the Bhatnagar-Gross-Krook(BGK) collision term to solve the convection-diffusion equation(CDE). A simulation was carried out in different ranges of the value of bound γ, which is related to skin capillary clearance and the volume of diffusion during a percutaneous absorption process. When a typical drug is used on the skin, the value of γ corresponds to the amount of drug absorbed by the blood and the absorption of the drug added to the skin. The effect of γ was studied for when the region of skin contact is a line segment on the skin surface.

Experimental and numerical investigation of threedimensional vortex structures of a pitching airfoil at a transitional Reynolds number

This research examines the vortex behaviors and aerodynamic forces in dynamic stall phenomena at a transitional Reynolds number(Re=90000)using experimental and numerical approaches.Periodic sinusoidal pitching motion at two different reduced frequencies is used to achieve the dynamic stall of a NACA 0012 airfoil.Several leading edge vortices form and detach in the dynamic stall stage.The flow then quickly transitions to a full separation zone in the stall stage when the angle of attack starts to decrease.There is discrepancy between the phaseaveraged and instantaneous flow field in that the small flow structures increased with angle of attack,which is a characteristic of the flow field at the transitional Reynolds number.The interaction between the streamwise vortices in the three-dimensional numerical results and the leading edge vortex are the main contribution to the turbulent flow.In addition,the leading edge vortex that supplies vortex lift is more stable at higher reduced frequency,which decreases the lift fluctuation in the dynamic stall stage.The leading edge vortex at higher reduced frequency is strong enough to stabilize the flow,even when the airfoil is in the down-stroke phase.

Effects of coarse riblets on air flow structures over a slender delta wing using particle image velocimetry

This research investigates the aerodynamic performance and flow characteristics of a delta wing with 65° sweep angle and with coarse axial riblets,and then compares with that of a smooth-surface delta wing.Particle Image Velocimetry(PIV)were utilized to visualize the flow over the wing at 6 cross-sections upright to the wing surface and parallel to the wing span,as well as 3 longitudinal sections on the leading edge,symmetry plane,and a plane between them at Angles of Attack(AOA)=20°and 30°and Re=1.2×10~5,2.4×10~5,and 3.6×10~5.The effects of the riblets were studied on the vortices diameter,vortex breakdown location,vortices distance from the wing surface,flow lines pattern nearby the wing,circulation distribution,and separation.The results show that the textured model has a positive effect on some of the parameters related to drag reduction and lift increase.The riblets increase the flow momentum near the wing’s upper surface except near the apex.They also increase the flow momentum behind the wing.

Multi-objective optimization of the kinematic parameters of fish-like swimming using a genetic algorithm method

This paper investigates the kinematic optimization of fish-like swimming.First,an experiment was performed to detect the motion of the fish tail foil of a fish robot.Next,the kinematic swimming model was verified experimentally using an image processing method.The model includes two rotational motions:caudal foil motion and foil-pitching motion.The kinematic model allows us to evaluate the influence of motion trajectory in the optimization process.To optimize the propulsive efficiency and thrust,a multi-objective genetic algorithm was employed to handle with kinematic,hydrodynamic,and propulsion models.The results show that the caudal length has a significant effect on the performance of the flapping foil in fish-like swimming,and its influence on the motion trajectory may increase the propulsive efficiency to as high as 98%in ideal conditions.The maximum thrust coefficient can also reach approximately 3 in ideal conditions.

A review on technologies with electricity generation potentials using liquified natural gas regasification cold energy

In modern times,worldwide requirements to curb greenhouse gas emissions,and increment in energy demand due to the progress of humanity,have become a serious concern.In such scenarios,the effective and efficient utilization of the liquified natural gas(LNG)regasification cold energy(RCE),in the economically and environmentally viable methods,could present a great opportunity in tackling the core issues related to global warming across the world.In this paper,the technologies that are widely used to harness the LNG RCE for electrical power have been reviewed.The systems incorporating,the Rankine cycles,Stirling engines,Kalina cycles,Brayton cycles,Allam cycles,and fuel cells have been considered.Additionally,the economic and environmental studies apart from the thermal studies have also been reviewed.Moreover,the discussion regarding the systems with respect to the regassification pressure of the LNG has also been provided.The aim of this paper is to provide guidelines for the prospective researchers and policy makers in their decision making.