Measurement of the flow structures in the wakes of different types of parachute canopies

We measured flow structures with stereoscopic particle image velocimetry(stereo-PIV) in the turbulent wakes of three parachute canopies, which had the same surface area, but different geometries. The tested parachute canopies included ribbon canopy, 8-branches canopy, and cross canopy. The obtained results showed that the geometry of the parachute canopies had significant influences on the flow structures in the wakes of these three canopies. In addition, the variation of Reynolds number did not lead to a dramatic change in the distributions of velocity, vorticity,Reynolds stress, and turbulent kinetic energy.

Multi-soliton fusion phenomenon of Burgers equation and fission, fusion phenomenon of Sharma-Tasso-Olver equation

A direct rational exponential scheme is proposed to construct exact multi-soliton solutions and its fission,fusion phenomena after interaction of the solitons has been discussed.We have considered the Burgers and Sharma-Tasso-Olver equation as two concrete examples to show the fission and fusion of the solitary wave and the solitons,respectively.We improve different structured multi-soliton solutions with possible conditions for fission and fusion of the Burgers and the Sharma-Tasso-Olver equations arises in plasma physics and in ocean dynamics.The amplitude and velocity relations between solitons and/or solitary waves before and after interactions are given and a possible condition for fission and fusion is proposed.Furthermore,three-dimensional plots of the wave solutions are given to visualize the dynamics of the model.©2017 Shanghai Jiaotong University.Published by Elsevier B.V.

Study of heat and mass transfer with Joule heating on magnetohydrodynamic(MHD)peristaltic blood flow under the influence of Hall effect

In this article,heat and mass transfer with Joule heating on magnetohydrodynamic(MHD)peristaltic blood under the influence of Hall effect is examined.Mathematical modelling is based on momentum,energy and concentration which are taken into account using ohms law.The governing partial differential equations are further simplified by neglecting the inertial forces and long wavelength approximations.Exact solutions have been presented for velocity,temperature and concentration profile.The influence of all the physical pertinent parameters is taken into account with the help graphs.It is found that Hartmann number and Hall parameter shows opposite behaviour on velocity,temperature and concentration profile.It is worth mentioning that pressure rise also depicts opposite behaviour for Hartmann number and Hall parameter.The present analysis is also presented for Newtonian fluid(α→0)as a special case for our study.It is observed that Hall Effect and magnetic field shows opposite behaviour on velocity and temperature profile.Temperature profile increases due to the increment in Prandtl number and Eckert number.Numerical comparison is also presented between the existing published results by takingα=0;M=0 as a special case of our study.

A study of heat and mass transfer on magnetohydrodynamic(MHD)flow of nanoparticles

Investigation of the flow,heat and mass transfer of a nanofluid over a suddenly moved flat plate is presented using Buongiorno's model.This study is different from some of the previous studies as the effects of Brownian motion and thermophoresis on nanoparticles volume fraction are passively controlled on the boundary rather than actively.The partial differential equations governing the flow are reduced to a system of nonlinear ordinary differential equations.Viable similarity transforms are used for this purpose.A well-known numerical scheme called Runge-Kutta-Fehlberg method coupled with shooting procedure has been used to find the solution of resulting system of equations.Discussions on the effects of different emerging parameters is provided using graphical aid.A table is also given that provides the results of different parameters on local Nusselt and Sherwood numbers.The passive control model can be used to control the boundary layer thickness as well as the rate of mass transfer at the wall.

Axisymmetric Powell-Eyring fluid flow with convective boundary condition: optimal analysis

The effects of axisymmetric flow of a Powell-Eyring fluid over an impermeable radially stretching surface are presented. Characteristics of the heat transfer process are analyzed with a more realistic condition named the convective boundary condition. Governing equations for the flow problem are derived by the boundary layer approximations. The modeled highly coupled partial differential system is converted into a system of ordinary differential equations with acceptable similarity transformations. The convergent series solutions for the resulting system are constructed and analyzed. Optimal values are obtained and presented in a numerical form using an optimal homotopy analysis method （OHAM）. The rheological characteristics of different parameters of the velocity and temperature profiles are presented graphically. Tabular variations of the skin friction coefficient and the Nusselt number are also calculated. It is observed that the temperature distribution shows opposite behavior for Prandtl and Biot numbers. Furthermore, the rate of heating/cooling is higher for both the Prandtl and Biot numbers.

Solution of analytical model for fuel spray penetration via homotopy perturbation method

The present paper attempts to solve equations in the initial stage and the two-phase flow regime of fuel spray penetration using the HPM-Padétechnique,which is a combination of the homotopy perturbation method(HPM)and Padéapproximation.At the initial stage,the effects of the droplet drag and the air entrainment were explained while in the two-phase flow stage,the spray droplets had the same velocities as the entrained air.The results for various injection pressures and ambient densities are presented graphically and then discussed upon.The obtained results for these two stages show a good agreement with previously obtained expressions via successive approximations in the available literature.The numerical result indicates that the proposed method is straight forward to implement,efficient and accurate for solving nonlinear equations of fuel spray.