Onset of instability of a flag in uniform flow

This paper numerically and analytically studies the onset of instability of a flag in uniform flow. The three-dimensional （3D） simulation is performed by using an immersed-boundary method coupled with a nonlinear finite element method. The global stability, bistability and instability are identified in the 3D simulations. The Squire＇s theorem is extended to analyze the stability of the fluid-flag system with 3D initial perturbations. It is found that if a parallel flow around the flag admits an unstable 3D disturbance for a certain value of the flutter speed, then a two-dimensional （2D） disturbance at a lower flutter speed is also adnfitted. In addition, the growth rate of 2D disturbance is larger than that of the 3D disturbance.

Red blood cell partitioning and blood flux redistribution in microvascular bifurcation

This paper studies red blood cell （RBC） partitioning and blood flux redistribution in microvascular bifurcation by immersed boundary and lattice Boltzmann method. The effects of the initial position of RBC at low Reynolds number regime on the RBC deformation, RBC partitioning, blood flux redistribution and pressure distribution are discussed in detail. It is shown that the blood flux in the daughter branches and the initial position of RBC are important for RBC partitioning. RBC tends to enter the higher-flux-rate branch if the initial position of RBC is near the center of the mother vessel. The RBC may enter the lower-flux-rate branch if it is located near the wall of mother vessel on the lower-flux-rate branch side. Moreover, the blood flux is redistributed when an RBC presents in the daughter branch. Such redistribution is caused by the pressure distribution and reduces the superiority of RBC entering the same branch. The results obtained in the present work may provide a physical insight into the understanding of RBC partitioning and blood flux redistribution in microvascular bifurcation.

Review on bio-inspired flight systems and bionic aerodynamics

Humans’initial desire for flight stems from the imitation of flying creatures in nature.The excellent flight performance of flying animals will inevitably become a source of inspiration for researchers.Bio-inspired flight systems have become one of the most exciting disruptive aviation technologies.This review is focused on the recent progresses in bio-inspired flight systems and bionic aerodynamics.First,the development path of Biomimetic Air Vehicles(BAVs)for bio-inspired flight systems and the latest mimetic progress are summarized.The advances of the flight principles of several natural creatures are then introduced,from the perspective of bionic aerodynamics.Finally,several new challenges of bionic aerodynamics are proposed for the autonomy and intelligent development trend of the bio-inspired smart aircraft.This review will provide an important insight in designing new biomimetic air vehicles.

ANALYTICAL SOLUTIONS OF NON-FOURIER PENNES AND CHEN-HOLMES EQUATIONS

The analytical solutions of non-Fourier Pennes and Chen Holmes equations are obtained using the Laplace transformation and particular solution method in the present paper. As an application, the effects of the thermal relaxation time % the blood perfusion wb, and the blood flow velocity v on the biological skin and inner tissue temperature T are stxldied in detail The results obtained in this study provide a good alternative method to study the bio-heat and a biophysical insight into the understanding of the heat transfer in the biotissue.