Controlling the destructive behavior of the wake region and consequently drag reduction are great challenges in fluid mechanics and ocean engineering. In this paper, the effect of the non-uniform magnetic field on controlling the flow and consequently drag reduction has been studied in laminar flow of magnetic nanofluid around a circular cylinder. The source of the magnetic field is a single current-carrying wire located in the center of the cylinder. The nanofluid consists of Fe₃O₄ as nanoparticles and water as the base flow. The ranges of Reynolds number (Re), volume fraction (ϕ), and the diameters of nanoparticles are 1.6 < Re < 180, 0 < ϕ < 0.04 and 15 < d_p < 25, respectively.

The modified Buongiorno model that contains the magnetophoresis term is utilized to perform two-phase modeling of magnetic nanofluid flow. Finite volume method and PISO (Pressure-implicit With Splitting Of Operators) algorithm are utilized for the discretization of the governing unsteady equations including conservation laws of mass, volume fraction transport, and momentum equations by considering the ferrohydrodynamics (FHD) force as the source term. The results showed a significant effect of magnetic field intensity and volume fraction on the flow parameters such as drag coefficient, strouhal number, wake length, etc. In general, increasing the magnetic field in various volume fractions and various nanoparticle diameters reduces the amount of drag coefficient. The effective parameters for flow controlling are ordered as follows regarding their effectiveness: magnetic field intensity, volume fraction and diameter of the nanoparticles, respectively.

在流体力学和海洋工程中，控制尾流区域的破坏性行为并因此降低阻力是巨大的挑战。在本文中，研究了非均匀磁场对磁纳米流体在圆柱体周围的层流中控制流量以及减阻作用的影响。磁场的来源是位于圆柱体中心的单根载流导线。纳米流体由作为纳米颗粒的Fe ₃ O ₄和作为基本流的水组成。雷诺数（Re），体积分数（volume）和纳米粒子的直径范围分别为1.6 <Re <180、0 <ϕ <0.04和15 <d _p <25。

修改后的Buongiorno模型（包含磁泳术语）被用于执行磁性纳米流体流的两相建模。通过将铁水动力（FHD）力作为源项，利用有限体积法和PISO（算子分裂的压力隐式）算法离散化控制非稳态方程，包括质量守恒律，体积分数输运和动量方程。 。结果表明，磁场强度和体积分数对流动参数（如阻力系数，Strouhal数，尾流长度等）具有显着影响。通常，增加各种体积分数和各种纳米粒子直径的磁场会减少阻力系数。