Numerical simulation of compressible viscous MHD flows for reducing supersonic drag of blunt bodies

Agarwal, Ramesh K.; Augustinus, Justin

doi:10.2514/6.1999-601

Cited by 11 publications

(3 citation statements)

References 2 publications

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“…Such interaction forms the basic idea of electromagnetic flow of supersonic flow. Many researchers have shown that supersonic flow can be altered significantly by Lorentz force [3][4][5][6][7][8][9] . It was found that MHD effects weaken the bow shock structure and significantly reduce the shock standoff distance for supersonic flow over a blunt body with the presence of an imposed magnetic field.…”

Section: Mhd Effects On Weakly Ionized Supersonic Flowsmentioning

confidence: 99%

Numerical Simulation of Supersonic Boundary Layer Stability with Applied Electromagnetic Field in a Weakly Ionized Flow

Singh

Zhong

Gogineni

2004

35th AIAA Plasmadynamics and Lasers Conference

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This paper investigates, by direct numerical simulation, the effect of an imposed electromagnetic field on a weakly ionized supersonic boundary layer in the range of 2.7 to 3.0 in a supersonic plasma wind tunnel, located at the non-equilibrium thermodynamics laboratory, under J. W. Rich and I. Adamovich, at the Ohio State University [1]. The main emphasis of the study is on MHD effects on the supersonic boundary layer. The imposed magnetic field is generated by a magnet flush-mounted in the tunnel side wall and the electric field is generated in this supersonic flow, pre-ionized by the RF discharge, by applying a DC field using electrodes flush-mounted in the top and bottom walls, perpendicular both to the flow velocity and the magnetic field. The electrical conductivity of the flow varies between 0.1 and 0.5 mho/m. The magnetic Reynolds number of the flow is small so that the induced magnetic field is neglected. The governing equations of the MHD flow, which are the Navier-Stokes equations with the applied electromagnetic force terms, are computed by a third-order upwinded numerical scheme. A series of cases with different imposed magnetic fields, electric fields and electrical conductivity, for two different stagnation pressures at the nozzle entrance, have been investigated for the mean flow. Calculations on the second mode instability are planned. It is found that in the presence of electric fields and the absence of magnetic fields, i.e. joule heating, the flow at the centerline heats up strongly leading to retardation in the flow velocity. The boundary layer thickness also increases and the mean Mach number is brought down. In the presence of magnetic field only, it is observed that the boundary layer profile changes depending on the direction of the field and, also the effect on the boundary layer is less in magnitude compared to the effect of joule heating on the same. The magnetic field is limited in its ability to mitigate the effects of an imposed electric field on the flow field. Unsteady calculations are currently underway and comprehensive conclusions on effects of external electromagnetic fields are expected in future. We have also undertaken three dimensional calculations to understand the effects of the sidewall on the flow profile.

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Section: Mhd Effects On Weakly Ionized Supersonic Flowsmentioning

confidence: 99%

Numerical Simulation of Supersonic Boundary Layer Stability with Applied Electromagnetic Field in a Weakly Ionized Flow

Singh

Zhong

Gogineni

2004

35th AIAA Plasmadynamics and Lasers Conference

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“…Such interaction forms the basic idea of electromagnetic modification of supersonic flow. Secondary flow expedites the process of transition to turbulence in the flow and many researchers have shown that supersonic flow can be altered significantly by Lorentz force [2][3][4][5][6][7][8][9][10][11][12][13] hence current study aims to investigate control of secondary flow in supersonic flow using electromagnetic forces.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Secondary Flow in a Weakly Ionized Supersonic Flow with Applied Electromagnetic Field

Rawat

Zhong

Singh

et al. 2005

36th AIAA Plasmadynamics and Lasers Conference

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This paper investigates, by numerical simulation of Navier Stokes equations, Magnetohydrodynamic (MHD) effects of an imposed electromagnetic field on secondary flow in a plasma wind tunnel with a weakly ionized supersonic flow in the range of Mach number 2.6 to 3.0. The imposed magnetic field is generated by a magnet flushmounted in the tunnel side wall. Flow is pre-ionized by an R-F discharge and DC electric field is generated in the flow by electrodes flush-mounted in the top and bottom walls, perpendicular both to the flow velocity and the magnetic field. The electrical conductivity of the flow varies between 0.1 and 0.5 mho/m. The magnetic Reynolds number of the flow is small so induced magnetic field is neglected. The governing equations of the MHD flow, which are the Navier-Stokes equations with the applied electromagnetic force terms, are computed by a third-order upwind numerical scheme. A series of cases with different imposed magnetic fields, electric fields and electrical conductivities, for two different stagnation pressures at the nozzle entrance, were investigated. A strong secondary flow was observed in the cold flow, i.e. flow with magnetic field and electric field switched off. However when a strong electric field is applied at constant electrical conductivity, the Mach number in the inviscid core is seen to drop. Also, the boundary layer thickness increases. More importantly, the strong cross flow is reduced downstream of the zone of electric field imposition. The negative magnetic field, acting in conjunction with the strong electric field further retards the flow and generates stronger secondary flow. To account for the scenario when time lag is large between application of electromagnetic field and Joule heating of flow, calculations were carried out by neglecting Joule heating terms in energy equation. Actual solutions are expected to be in between those obtained with and without considering Joule heating effects. In absence of Joule heating, constant acceleration (retardation) of flow was observed with accelerating (retarding) electromagnetic field although the changes in flow properties were minor as compared to the Joule heated flow with same electromagnetic fields. Under the assumption of no Joule heating, accelerating magnetic fields reduce the secondary flow while retarding flow makes the secondary flow stronger. Flow with a lower Reynolds number is expected to be more stable because of viscous effects. On the contrary, secondary flow near side wall is observed to be stronger for cold flows of lower Reynolds number. Also, Lower Reynolds number flow is observed to be affected more strongly by applied electromagnetic forces. In general, an accelerating magnetic field applied with electric field was observed to produce much lower secondary flow than the retarding magnetic field in same situation for almost all of the cases considered in the study.

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“…Furthermore, the revelation of a Soviet hypersonic plane—the AJAX project—demonstrated for the first time a potential real-world application of hypersonic MHD flow control. This work on MHD hypersonic flow was continued by many researchers [ 18 – 21 ], who conducted both physical experiments and computational methods for hypersonic MHD flow over blunt bodies. More recently, Grigoriadis et al [ 22 ] computed hypersonic MHD flow past a cylinder using the immersed boundary method.…”

Section: Introductionmentioning

confidence: 99%

Magnetohydrodynamic Simulations of Hypersonic Flow over a Cylinder Using Axial‐ and Transverse‐Oriented Magnetic Dipoles

Guarendi

Chandy

2013

The Scientific World Journal

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Numerical simulations of magnetohydrodynamic (MHD) hypersonic flow over a cylinder are presented for axial- and transverse-oriented dipoles with different strengths. ANSYS CFX is used to carry out calculations for steady, laminar flows at a Mach number of 6.1, with a model for electrical conductivity as a function of temperature and pressure. The low magnetic Reynolds number (≪1) calculated based on the velocity and length scales in this problem justifies the quasistatic approximation, which assumes negligible effect of velocity on magnetic fields. Therefore, the governing equations employed in the simulations are the compressible Navier-Stokes and the energy equations with MHD-related source terms such as Lorentz force and Joule dissipation. The results demonstrate the ability of the magnetic field to affect the flowfield around the cylinder, which results in an increase in shock stand-off distance and reduction in overall temperature. Also, it is observed that there is a noticeable decrease in drag with the addition of the magnetic field.

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Numerical simulation of compressible viscous MHD flows for reducing supersonic drag of blunt bodies

Cited by 11 publications

References 2 publications

Numerical Simulation of Supersonic Boundary Layer Stability with Applied Electromagnetic Field in a Weakly Ionized Flow

Numerical Simulation of Supersonic Boundary Layer Stability with Applied Electromagnetic Field in a Weakly Ionized Flow

Numerical Simulation of Secondary Flow in a Weakly Ionized Supersonic Flow with Applied Electromagnetic Field

Magnetohydrodynamic Simulations of Hypersonic Flow over a Cylinder Using Axial‐ and Transverse‐Oriented Magnetic Dipoles

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