磁场对具有压力梯度的低频振荡自然对流的影响

G. C. 夏玛; M. 简妮; M. 察尼特拉; 何吉欢

磁场对具有压力梯度的低频振荡自然对流的影响

基础科学院数学科学院坎大瑞亚格拉-28202 印度

基金项目: 新德里CSIR资助项目(25(0098)/97/EMR-Ⅱ)

详细信息

中图分类号: O482.51
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出版历程
- 收稿日期: 2001-09-04
- 修回日期: 2002-07-18
- 刊出日期: 2003-03-15

The Effect of Magnetic Fields on Low Frequency Oscillating Natural Convection With Pressure Gradient

School of Mathematical Sciences, Institute of Basic Science, Khandari, Agra-282002, India

摘要

摘要: 研究了磁场对具有非定常压力梯度的振荡自然对流的影响。假设流体是在两平行板内流动。由于在航天材料中的重要性,重点研究在微重力作用下由于g-振荡器诱发的低频振荡自然对流。得到了在非定常磁场下的振荡流体的一般解。还给出了一些特殊的振荡流和对作用磁场的响应。发现振荡流的性质依赖于频率、驱动浮力的振幅、温度梯度、磁场、壁面的导电情况。当没有磁场时,浮力在驱动流体振荡中起主导作用,并且速度的大小还受温度梯度的影响。为了控制振荡流,可以应用外磁场。还发现:当壁面是导体时,速度的减小与作用磁场的平方成反比;当壁面是绝缘体时,速度的减小与作用磁场成反比。一些详细的计算结果反映了真实的状态。
- 对流 /
- g-振荡加速器 /
- 浮力 /
- 磁场 /
- 压力梯度
Abstract: The oscillating natural convection in the presence of transverse magnetic field with time depending pressure gradient is studied.The analysis of the problem is carried out by assuming that the fluid is flowing in a parallel plate configuration.The emphasis is on low frequency oscillating convective flows induced by g-jitter associated with micro gravity because of their importance to the space processing materials.A general solution for an oscillating flow in the presence of transverse magnetic field is carried out.Some special cases of the oscillating flow and its response to an applied magnetic field are performed.It was observed that the behavior of oscillating free convective flows depends on frequency, amplitude of the driving buoyancy forces, temperature gradient, magnetic field and the electric conditions of the channel walls.In the absence of magnetic field, buoyancy force plays a predominant role in driving the oscillatory flow pattern, and velocity magnitude is also affected by temperature gradients.To suppress the oscillating flow external magnetic field can be used.It is also found that the reduction of the velocity is inversely proportional to the square of the applied magnetic field with conducting wall but directly proportional to the inverse of the magnetic field with insulating wall.Detailed calculations and computational results are also carried out to depict the real situation.
- convection /
- g-jitter acceleration /
- buoyancy force /
- magnetic field /
- pressure gradient

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参考文献(17)

[1]	Bejan A.The method of scale analysis:Natural convection in porous media[A].In:S Kakac,W Aung,R Viskana Eds.Nataral Convection:Fundamentals and Applications[C].Hemisphere,Washington D C:Pergamon Press Ltd,1985,548-572.
[2]	Spainer T,Oldham K B.An Atlas of Functions[M].Hemisphere of Washington D C,1987.
[3]	Keith W L.Spectral measurements of pressure fluctuations on riblets[J].American Institute of Aeronautics and Astronautics Journal,1989,27:1822-1824.
[4]	Merkin J H,Mahmood T.On the free convection boundary layer on a vertical plate with prescribed surface heat flux[J].Journal of Engineering Mathematics,1990,24:95-107.
[5]	Manoha E.Wall pressure wave number frequency spectrum beneath a turbulent boundary layer measured with transducers calibrated with an acoustical method[A].[J].In:Proceedings of the ASME Symposium on Flow Noise Modeling Measurement and Control[C].Noise Control and Acoustics,1991,11:21-35.
[6]	Herbert K,Leehey P.Wall pressure spectrum in a flat plate turbulent boundary layer and down stream of a turbulent boundary layer manipulator[A].[J].In:Proceedings of the ASME Symposium on Flow-Induced Vibration and Control[C].Noise Center,Acoustics,1992,11(29):55-68.
[7]	Casademunt J,Zhang W,Venals J,et al.Numerical modeling on characterization and quantification[J].AIAA J,1993,31(11):20-27.
[8]	Panton R L,Robert G.The wave number-phase velocity representation for the turbulent wall pressure spectrum[J].ASME,J Fluid Engineering,1994,116:477-483.
[9]	Abraham B M,Keith W L.Analysis of the wall pressure field from a numerical simulation of turbulent channel flow[A].[J].In:Proceedings of the ASME Symposium on Flow Noise Modeling Measurements and Control[C].Noise Cotrol and Acoustics,1995,19(29):55-65.
[10]	Wright S D,Ingham D B.On natural convection from a vertical plate with a prescribed surface heat flux in porous media[J].Transport in Porous Media,1996,22:181-193.
[11]	Sharma G C,Jain M,Saral R N.The effects of non-zero bulk flow and non-mixing on diffusion with variable transfer of the solute[J].Internat J Appl Sci Comput,1998,4:201-210.
[12]	Li B Q.The effect of magnetic fields on low freguency oscillating natural convection[J].Internat J Engrg Sci,1996,34(15):1369-1383.
[13]	Keith W L,Abraham B M.Effects of Convection and decay of turbulent on the wall pressure wave number-frequency spectrum[J].ASME J Fluid Engrg,1997,119(21):50-55.
[14]	Raptis A.Flow of micro polar fluid past a continuously moving plate by the presence of radiation[J].Intetrnational Journal of Heat Mass Transfer,1998,41:2865-2866.
[15]	Acharya M,Singh L P,Dash G C.Heat and mass transfer over an accelerating surface with heart source in presence of suction and blowing[J].Internat J Engrg Sci,1999,37(32):189-211.
[16]	Chamkha A J.Thermal radiation and buoyancy effects on hydro-magnetic flow over an accelerating permeable surface with heat source or sink[J].Internat J Engrg Sci,2000,38:1699-1712.
[17]	Kim Y J.Unsteady MHD convective heat transfer past a semi-infinite vertical porous moving plate with variable suction[J].Internat J Engrg Sci,2000,38(20):833-845.