电磁力对潜艇绕流流场局部扰动优化效果
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摘要
潜艇水下航行时,由于流体粘性的存在导致流动分离、壁面边界层转捩等问题,使得潜艇阻力增大,产生了大量的涡并伴随有涡的不规则脱落。文中基于粘性不可压Navier-Stokes控制方程,使用有限体积法对Re=107潜艇流场进行数值仿真,分析不同作用系数的电磁力分别施加于A=1, A=2, A=3情况下的潜艇绕流流场结构和受力变化。结果表明,当作用电磁力系数N=1.5的电磁力施加于半球艏部与中体艇身交界处(A=1, N=1.5)时,艇身的涡结构被有效抑制,对围壳顶盖的控制(A=2, N=1.5)则可以有效抑制涡脱落现象,同时阻力下降最多。由此可知,合理利用适当的电磁力控制围壳边界层的流动能有效抑制不规则涡的产生及其脱落,减少流噪声,有助于提高潜艇的隐蔽性及动力性能。文中研究可为进一步研究优化潜艇流场问题提供参考。
While a submarine navigates underwater, the drag against submarine increases for the reasons such as flow separation and boundary layer transition near the wall, which are resulted from fluid viscosity. Meanwhile, massive vortices appear in the flow field accompanied by abnormal vortex shedding. Based upon the viscous incompressible Navier-Stokes equation, this study employs the finite volume method to numerically simulate the submarine's flow field with Re=107. The flow field and the force evolution on the submarine are analyzed respectively under the conditions of A=1, A=2, and A=3, where electromagnetic force(Lorentz force) is applied for flow field control. The results show that the vortices on the hull are effectively suppressed when the Lorentz force is applied to the junction of the hemispherical forebody and midbody(A=1, N=1.5). Applying Lorentz force to the top of fin(A=2, N=1.5) can effectively suppress the vortex shedding, and greatly reduce the drag force(horizontal component of force). Therefore, appropriate utilization of Lorentz force for controlling the boundary layer flow of the fin may efficaciously suppress the formation of irregular vortices and their shedding, and reduce flow noises, hence improve the stealth and the dynamic performance of a submarines. This study may provide a reference for optimization of submarine flow field.
While a submarine navigates underwater, the drag against submarine increases for the reasons such as flow separation and boundary layer transition near the wall, which are resulted from fluid viscosity. Meanwhile, massive vortices appear in the flow field accompanied by abnormal vortex shedding. Based upon the viscous incompressible Navier-Stokes equation, this study employs the finite volume method to numerically simulate the submarine's flow field with Re=107. The flow field and the force evolution on the submarine are analyzed respectively under the conditions of A=1, A=2, and A=3, where electromagnetic force(Lorentz force) is applied for flow field control. The results show that the vortices on the hull are effectively suppressed when the Lorentz force is applied to the junction of the hemispherical forebody and midbody(A=1, N=1.5). Applying Lorentz force to the top of fin(A=2, N=1.5) can effectively suppress the vortex shedding, and greatly reduce the drag force(horizontal component of force). Therefore, appropriate utilization of Lorentz force for controlling the boundary layer flow of the fin may efficaciously suppress the formation of irregular vortices and their shedding, and reduce flow noises, hence improve the stealth and the dynamic performance of a submarines. This study may provide a reference for optimization of submarine flow field.
引文
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[2]Shariati S K,Mousavizadegan S H.The Effect of Appendages on the Hydrodynamic Characteristics of an Underwater Vehicle Near the Free Surface[J].Applied Ocean Research,2017,67:31-43.
[3]Chen L,Gillivray I M.Characteristics of Sound Radiation by Turbulent Flow over a Hydrofoil and a Bare-hull SUBOFF[C]//Australian Acoustical Society Conference2011,Acoustics 2011:Breaking New Ground.Gold Coast,Australia:Proceedings of Acoustics,2011:443-450.
[4]Berger T W,Kim J,Lee C,et al.Turbulent Boundary Layer Control Utilizing the Lorentz Force[J].Physics of Fluids,2000,12(3):631-649.
[5]张辉,范宝春,贺旺,等.电磁力作用下的绕流减阻与优化控制[J].兵工学报,2010,31(10):1291-1297.Zhang Hui,Fan Bao-chun,He Wang,et al.Drag Reduction and Optimal Control of Cylinder Wake via Lorentz Force[J].Acta Armamentarii,2010,31(10):1291-1297.
[6]Ask J,Davidson L.A Numerical Investigation of the Flow Past a Generic Side Mirror and its Impact on Sound Generation[J].Journal of Fluids Engineering,2009,131(6):061102.
[7]Huang Y D,Zhou B M,Tang Z L,et al.Transition Scenario and Transition Control of The Flow over a Semi-infinite Square Leading-edge Plate[J].Physics of Fluids,2017,29(7):074105.
[8]刘宗凯,薄煜明,王军,等.电磁力滤波与快速反射镜光学补偿在潜航器光轴稳定控制中的应用[J].物理学报,2017,66(8):084704.Liu Zong-Kai,Bo Yu-Ming,Wang Jun,et al.Lorentz Force Filtering and Fast Steering Mirror Optical Compensation in Optical Axis Stability Control for Photoelectric Mast[J].Acta Physica Sinica,2017,66(8):084704.
[9]Zhang H,Fan B C,Chen Z H.Numerical Study of the Suppression Mechanism of Vortices-induced Vibration by Symmetric Lorentz Forces[J].Journal of Fluids and Structures,2014,48:62-80.
[10]Altintas A,Davidson L.Direct Numerical Simulation Analysis of Spanwise Oscillating Lorentz Force in Turbulent Channel Flow at Low Reynolds Number[J].Acta Mechanica,2017,228(4):1269-1286.
[11]Lim S,Choi B.A Study on the MHD(magneto hydrodynamic)Micropump with Side-walled Electrodes[J].Journal of Mechanical Science and Technology,2009,23(3):739-749.
[12]Albrecht T,Stiller J,Metzkes H.Electromagnetic Flow Control in Poor Conductors[J].The European Physical Journal Special Topics,2013,220(1):275-285.
[13]Liu H X,Zhou B M,Liu Z K,et al.Numerical Simulation of Flow around a Body of Revolution with an Appendage Controlled by Electromagnetic Force[J].Journal of Aerospace Engineering,2013,227(2):303-310.
[14]Breuer K S,Park J,Henoch C.Actuation and Control of a Turbulent Channel Flow Using Lorentz Forces[J].Physics of Fluids,2004,16(4):897-907.