Evolution simulation of lightning discharge based on a magnetohydrodynamics method

In order to solve the load problem for aircraft lightning strikes, lightning channel evolution is simulated under the key physical parameters for aircraft lightning current component C. A numerical model of the discharge channel is established, based on magnetohydrodynamics （MHD） and performed by FLUENT software. With the aid of user-defined functions and a user- defined scalar, the Lorentz force, Joule heating and material parameters of an air thermal plasma are added. A three-dimensional lightning arc channel is simulated and the arc evolution in space is obtained. The results show that the temperature distribution of the lightning channel is symmetrical and that the hottest region occurs at the center of the lightning channel. The distributions of potential and current density are obtained, showing that the difference in electric potential or energy between two points tends to make the arc channel develop downwards. The arc channel comes into expansion on the anode surface due to stagnation of the thermal plasma and there exists impingement on the copper plate when the arc channel comes into contact with the anode plate.

Fractional Analysis of Thin Film Flow of Non-Newtonian Fluid

Modeling and analysis of thin film flow with respect to magneto hydro dynamical effect has been an important theme in the field of fluid dynamics,due to its vast industrial applications.The analysis involves studying the behavior and response of governing equations on the basis of various parameters such as thickness of the film,film surface profile,shear stress,liquid velocity,volumetric flux,vorticity,gravity,viscosity among others,along with different boundary conditions.In this article,we extend this analysis in fractional space using a homotopy based scheme,considering the case of a Non-Newtonian Pseudo-Plastic fluid for lifting and drainage on a vertical wall.After applying similarity transformations,the given problems are reduced to highly non-linear and inhomogeneous ordinary differential equations.Moreover,fractional differential equations are obtained using basic definitions of fractional calculus.The Homotopy Perturbation Method(HPM),along with fractional calculus is used for obtaining approximate solutions.Physical quantities such as the velocity profile,volume flux and average velocity respectively for lift and drainage cases have been calculated.To the best of our knowledge,the given problems have not been attempted before in fractional space.Validity and convergence of the obtained solutions are confirmed by finding residual errors.From a physical perspective,a comprehensive study of the effects of various parameters on the velocity profile is also performed.Study reveals that Stokes number St,non-Newtonian parameterand magnetic parameter M have inverse relationship with fluid velocity in lifting case.In the drainage case,Stokes number St and non-Newtonian parameterhave direct relationship with fluid velocity,but magnetic parameter M shows inverse relationship with velocity.The investigation also shows that the fractional parameterhas direct relationship with the fluid velocity in lifting case,while it has inverse relationship with velocity in the drainage case.