Hartmann number

About: Hartmann number is a research topic. Over the lifetime, 2593 publications have been published within this topic receiving 61342 citations.

Effect of Magnetic Field on Pulsatile Blood Flow Through an Inclined Circular Tube with Periodic Body Acceleration

Abstract: A mathematical model has been developed for studying the characteristics of blood flow in a rigid inclined circular tube with periodic body acceleration under the influence of a uniform magnetic field. The blood is supposed to be couple stress fluid. Finite Hankel and Laplace transforms are used to obtain the analytical expressions for velocity profile, flow rate and acceleration of blood. The flow velocity deviates with various parameters such as Hartmann number, gravitational parameter, body acceleration, inclination angle, time etc. and this deviation of flow velocity can be regulated by a proper use of magnetic field.

Lattice Boltzmann modeling of MHD free convection of nanofluid in a V-shaped microelectronic module

Abstract: The mathematical modeling of MHD free convection thermal flow in a tilted V-shaped electronic assembly, packed with Cu-water nanofluid is numerically performed. The physical domain considered in this study is designed by two V-shaped active walls connected by two closed insulated walls. The cold partition is kept at temperature T c while the hot one consists of seven bands, alternately maintained at temperature T h and insulated from the environment. The lattice Boltzmann method with the D2Q9 lattice form is employed to solve the governing equations. This review covers a wide range of module inclination angle ( 0 ° ⩽ γ ⩽ 225 ° ), module aspect ratio ( 0.2 ⩽ AR ⩽ 0.8 ), Hartmann number ( 0 ⩽ Ha ⩽ 80 ), concentration of nanoparticles ( 0 % ⩽ ϕ ⩽ 6 % ) and Rayleigh number ( 10 4 ⩽ Ra ≤ 10 6 ). The results demonstrated that the average Nusselt number rises with an increase in the nanoparticles concentration and the Rayleigh number, but it reduces with increasing the module aspect ratio and the Hartmann number. Moreover, the heat flow rate is remarkably influenced by the module inclination angle at γ = 45 ° . Further, the correlations of average Nusselt number with pertinent parameters are proposed which optimizing the reliability of the system performance.

Wall modes in magnetoconvection at high Hartmann numbers

Abstract: Three-dimensional turbulent magnetoconvection at a Rayleigh number of in liquid gallium at a Prandtl number is studied in a closed square cell for very strong external vertical magnetic fields in direct numerical simulations which apply the quasistatic approximation. As , or equivalently the Hartmann number , are increased, the convection flow, which is highly turbulent in the absence of magnetic fields, crosses the Chandrasekhar linear stability limit for which thermal convection ceases in an infinitely extended layer and which can be assigned a critical Hartmann number . Similar to rotating Rayleigh–Benard convection, our simulations reveal subcritical sidewall modes that maintain a small but finite convective heat transfer for . We report a detailed analysis of the complex two-layer structure of these wall modes, their extension into the cell interior, and a resulting sidewall boundary layer composition that is found to scale with the Shercliff layer thickness.