Magnetohydrodynamic Interaction Research Articles

A Conceptual Modeling Approach for Performance of Magnetohydrodynamic Drag During Planetary Entry

Future higher-mass Mars missions present numerous engineering challenges and will require significant technological development, particularly of the entry, descent, and landing systems. One such development concept utilizes magnetohydrodynamic interaction with the plasma created during hypersonic planetary entry for energy generation, drag augmentation, and heat-flux mitigation. In this study, a performance estimation methodology for magnetohydrodynamic drag augmentation during Mars entry compatible with conceptual design is developed. A demonstrative investigation utilizing the developed methodology is then conducted, and simulated trajectory results are presented for various entry vehicles and magnetic field strengths. The study results show potential for significant magnetohydrodynamic drag augmentation during hypersonic entry at Mars, with calculated effective ballistic coefficient- reduction factors of up to 4, across entry vehicles ranging in mass from 70 MT to 4 MT. These results show that magnetohydrodynamic drag augmentation can have comparable impact to significant aeroshell diameter increases and also suggest that it could prove an effective form of drag-augmentation control authority by varying the applied magnetic field.

Numerical Study of Plasma Characteristics Under Magnetohydrodynamic Flow Control in Mars Entry

Magnetohydrodynamic flow control is an active thermal protection method for atmospheric entry vehicles. This study examined the plasma characteristics under magnetohydrodynamic flow control and its thermal protection ability at multiple altitudes (20–60 km) on a typical direct Mars entry path using numerical simulation considering the Hall effect. The simulation considered a spherical-conical capsule with an entry velocity of 8 km/s at an altitude of 60 km, equipped with a dipole magnet generating a magnetic field of approximately 0.3 T at the stagnation point of the capsule. The results showed that magnetohydrodynamic flow control can mitigate convective aerodynamic heating at high altitudes (45 km or more), where the high electrical conductivity of the plasma creates strong magnetohydrodynamic interaction. In contrast, at low altitudes (35 km or less), magnetohydrodynamic flow control is ineffective owing to low electrical conductivity. The high electrical conductivity at high altitudes is attributed not only to large flight velocities under low atmospheric pressures but also to the enlargement of the shock layer owing to the strong magnetohydrodynamic interaction, which expands the ionization progression area. Furthermore, the results indicated that considering the Hall effect in the numerical modeling of magnetohydrodynamic flow control in Mars direct entry is essential.

A Spatially Resolved X-Ray Polarization Map of the Vela Pulsar Wind Nebula

In this paper, we present a full spatially resolved polarization map for the Vela pulsar wind nebula (PWN) observed by IXPE. By employing effective background discrimination techniques, our results show a remarkably high degree of local polarization in the outskirt region, exceeding 60% (55%) with a probability of 95% (99%), which approaches the upper limit predicted by the synchrotron emission mechanism. The high degree of polarization suggests that the turbulent magnetic energy is at most 33% of the ordered one. In addition, the X-ray polarization map exhibits a toroidal magnetic field pattern that is consistent with the field revealed by radio observations across the entire nebula. This consistency reveals that the observed X-ray and radio emissions are radiated by electrons from the same magnetic field. Different from the Crab PWN, the consistency observed in the Vela PWN may be attributed to the interaction between the reverse shock of the supernova blast wave and the PWN, which leads to a displacement between the synchrotron-cooled nebula and the fresh nebula close to the pulsar. These findings deepen our understanding of the structure and evolution of the Vela PWN and the magnetohydrodynamic interaction in PWNe.

Magnetic field control of high-enthalpy shock wave/boundary-layer interactions using a fully implicit thermochemical non-equilibrium solver

Magnetohydrodynamic (MHD) heat shield systems have been proven to be highly effective in hypersonic blunt-nosed bodies. Thus, it is natural to consider the application of MHD to more complex geometries that induce shock wave/boundary-layer interactions associated with locally high heat load, which is a lack of deep research, especially for the large-size model in high-enthalpy conditions. To investigate the possibility and mechanism of the control of shock wave/boundary-layer interactions using local magnetic fields, the partially ionized flow of the hollow cylinder/flare coupling of these fields was numerically analyzed using a hypersonic thermochemical nonequilibrium solver. It consisted of an 11-species reaction model and a Park two-temperature model based on the low magneto-Reynolds assumption. To address the numerical stiffness introduced by the large difference in the characteristic time of the thermochemical non-equilibrium and grid refinement in the boundary layer and interaction zone, a fully implicit block lower–upper symmetric Gauss–Seidel algorithm was developed. This algorithm improved the accelerating rate and the solver was validated using cases involving MHD control of flow around a typical reentry vehicle, and the measured double cone and hollow cylinder/flare data for a high-enthalpy wind tunnel. After that, a parametric study of high-enthalpy flow over the hollow cylinder/flare model was conducted and MHD control was divided into three categories. Among these, N-type control led to the largest reduction in the peak value of the total wall heat flux near the neck region, which was obtained using a uniform magnetic field. Specifically, the peak heat flux and the peak skin friction coefficient were reduced by 20.0% and 48.0%, respectively. Then, two local MHD interaction parameters were newly proposed for mechanism analysis and can serve as an effective indicator for MHD controllability. The numerical results demonstrated that the Lorentz force in the counter-streamlined direction induced by the external magnetic field and ionized flow were key factors that influenced the control of the local heat flux. The results of this study lay the foundation for the design of MHD experiments in a high-enthalpy wind tunnel.

NUMERICAL STUDY OF BIOMAGNETIC MAXWELL FLUID PAST A NONLINEARLY STRETCHING SHEET WITH CONSIDERING MAGNETIZATION AND ELECTRICAL CONDUCTIVITY

This study goal is to examine the flow of two-dimensional biomagnetic Maxwell fluid past a nonlinearly stretched sheet while it is subject to an applied magnetic field that is produced by the presence of a magnetic dipole. Assumedly, the fluids magnetization M varies linearly with temperature T and magnetic field strength H. Consideration is given to the effects of magnetohydrodynamics (MHDs) and ferrohydrodynamics (FHDs) on the flow. The controlling nonlinear partial differential equation is presented with similarity transformations to change it into coupled ordinary differential equations. These equations are then numerically solved with the help of common finite differences method. The influence of the addressed problem parameters, namely, magnetic parameter [Formula: see text], ferromagnetic parameter [Formula: see text], Deborah number [Formula: see text] and nonlinear stretching parameter [Formula: see text] on the flow profile is discussed with the help of graphical demonstration. The obtained results show that the fluid velocity increases near the wall but its reverse after a fixed point from the wall with increases nonlinearity stretching parameter. The study also demonstrates that as the magnetic field intensity increases, the temperature distributions increase while the fluid velocity decreases. It was also discovered that, in contrast to the situation of pure hydrodynamics, the effect of MHD or FHD interaction is to slow down the fluid velocity. By making numerous comparisons with previously published work, the numerical method accuracy is examined, and the comparisons show that the results are generally in good accord. Along with the flow parameters, physical parameters like the dimensionless Nusselt number and the skin friction coefficient are shown. The study will be crucial for applications in medicine.

A reduced speed-of-light formulation of the magnetohydrodynamic-particle-in-cell method

ABSTRACT A reduced speed-of-light (RSOL) approximation is a useful technique for magnetohydrodynamic (MHD)-particle-in-cell (PIC) simulations. With an RSOL, some ‘in-code’ speed-of-light $\tilde{c}$ is set to much lower values than the true c, allowing simulations to take larger time-steps (which are restricted by the Courant condition given the large CR speeds). However, due to the absence of a well-formulated RSOL implementation from the literature, with naive substitution of the true c with a RSOL, the CR properties in MHD-PIC simulations (e.g. CR energy or momentum density, gyro radius) vary artificially with respect to each other and with respect to the converged ($\tilde{c} \rightarrow c$) solutions, with different choices of a RSOL. Here, we derive a new formulation of the MHD-PIC equations with an RSOL and show that (1) it guarantees all steady-state properties of the CR distribution function, and background plasma/MHD quantities are independent of the RSOL $\tilde{c}$ even for $\tilde{c} \ll c$; (2) it ensures that the simulation can simultaneously represent the real physical values of CR number, mass, momentum, and energy density; (3) it retains the correct physical meaning of various terms like the electric field; and (4) it ensures the numerical time-step for CRs can always be safely increased by a factor $\sim c/\tilde{c}$. This new RSOL formulation should enable greater self-consistency and reduced CPU cost in simulations of CR–MHD interactions.

Principles of Magnetohydrodynamical Control of Internal and External Supersonic Flows

This paper demonstrates the possibility of active magnetohydrodynamic (MHD) control of supersonic flows containing shock waves. The shock wave configurations that occur at the inlet to a supersonic diffuser and in front of a streamlined semicylindrical model are used for the purpose of investigation. The impact is carried out by organizing local gas discharge regions when applying a magnetic field transverse to gas discharge currents. It has been shown that by changing the local region of application, the intensity and the direction of the gas discharge currents, it is possible to change the intensity and direction of the ponderomotive force acting on the gas flow during MHD interaction. The ponderomotive force control allows for acting locally on the shape and position of shock waves, the speed and direction of the flow, and the increase or reduction of pressure near the surface of the streamlined body. The experiments were carried out on a gas dynamic setup based on a shock tube in a gas dynamic path, capable of creating supersonic flows in a wide range of Mach numbers at M = 4–7. There was a possibility of organizing the electric and pulsed magnetic fields with an intensity of up to 1.5 T. The given experimental Schlieren flow patterns and the analysis of the obtained data demonstrate the MHD effect on: the change in the angle of inclination of the attached shocks, both into increase and decrease; the bow shock wave approaching the body or the removal from it; and the change in the aerodynamic drag and lift force of the streamlined bodies.

Numerical Study of Unsteady Boundary Layer Flow of a Biomagnetic Fluid over a Horizontal Stretching Sheet with Magnetic Dipole

This paper focuses on the theoretical and numerical investigation of the unsteady, viscous, incompressible, two-dimensional laminar boundary layer flow of a Newtonian biomagnetic fluid over a stretching sheet under the influence of an applied magnetic field in the presence of heat transfer. The magnetic field is induced by a magnetic dipole placed below the stretching sheet. The magnetic field intensity represents the magneto-thermo-mechanical coupling. This allows exclusion of the biofluid that is distant from the sheet at Curie temperature to avoid further magnetization. The unsteadiness of the flow is discernible in the fluid flow properties. The mathematical model of the problem conforms to the principles of Magnetohydrodynamics (MHD) and Ferrohydrodynamics (FHD). In this work, the study is performed on a specific biofluid, human blood. The modified Stokes principle is used to implement the model under the assumption that along with the three thermodynamic variables P, ρ, and T, the Biomagnetic Fluid Dynamics (BFD) fluid behavior can be characterized as a function of magnetization M. To describe the physical problem, a coupled non-linear system of ordinary differential equations subject to appropriate boundary conditions is derived from Navier-Stokes and thermal energy equations by performing non-dimensionalization of the considered variables. To solve these equations, the dsolve routine in the MAPLE software is used. Numerical results for flow profiles and the local skin friction coefficient (Cfx) and the local Nusselt number (Nux) are discussed for different values of unsteadiness parameter (A), biomagnetic interaction parameter (B) and a rational quantity (ϵ). The achieved results are compared with previously published work for steady state flow, and they seem to be in good agreement. It is found that MHD and FHD interaction parameters affect significantly on the velocity, temperature and pressure field. A successful completion will bring interesting results for better understanding of the biomagnetic fluid flow characteristics and can be beneficial to medical and bioengineering applications; particularly for estimating the characteristics of blood flow in stenosed arteries.

Three-Dimensional Analysis of the Influence of the Magnetic Flux Density on Minimum PR in a Faraday-Type MHD Channel

The magnetohydrodynamic (MHD) behavior and performance characteristic have been revealed by 3-D numerical simulation of the Faraday-type MHD generator. Numerical results show that the generator inlet–outlet pressure ratio (PR) will affect the plasma behaviors and generator performance in the channel. At high PR, the plasma flows at supersonic, and higher electric power [enthalpy extraction rate (EE)] can be obtained. However, at low PR, boundary layer separation occurs with deflected flow of velocity streamlines and vortex in the separated flow region, owing to the oblique shock wave. Therefore, there exists a minimum PR to maximize power generation performance. Under the strong MHD interaction, the Lorentz force causes the loss of Mach number and the increase of static pressure, but it can alleviate the effect of oblique shock for a lower PR. Furthermore, suppressing the boundary layer separation effect gradually evolves into a normal shock wave. When PR is higher, the thermoelectric conversion efficiency increases, and then a weak shock wave will be generated in the channel, which will propagate upstream and evolve into a normal shock wave. Consequently, under a higher magnetic flux density, the minimum PR can be effectively reduced, and the best generator performance can be obtained. In addition, an “ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$M$ </tex-math></inline-formula> ”-shaped velocity profile will be generated due to the significantly increased MHD interaction. The results calculated in the present simulation are valuable and important for setting working gas conditions and evaluating generator performance.

MHD R&amp;D Activities for Liquid Metal Blankets

According to the most recently revised European design strategy for DEMO breeding blankets, mature concepts have been identified that require a reduced technological extrapolation towards DEMO and will be tested in ITER. In order to optimize and finalize the design of test blanket modules, a number of issues have to be better understood that are related to the magnetohydrodynamic (MHD) interactions of the liquid breeder with the strong magnetic field that confines the fusion plasma. The aim of the present paper is to describe the state of the art of the study of MHD effects coupled with other physical phenomena, such as tritium transport, corrosion and heat transfer. Both numerical and experimental approaches are discussed, as well as future requirements to achieve a reliable prediction of these processes in liquid metal blankets.

Magnetohydrodynamic Aerobraking Shock Stand-Off Measurements with Flight Representative Electrodynamic Boundary Conditions

This paper reports on an experimental study of magnetohydrodynamic aerobraking using an expansion tube facility, which can generate the correct electrodynamic boundary conditions for spacecraft atmospheric entry. Argon test gas was selected for its relatively simple chemistry, making it well suited to develop experimental test cases for numerical code development. Test models were constructed from either spherical neodymium permanent magnets or steel balls. Ceramic paint was used as an electrically insulating surface boundary condition for experiments where this was required. Finite-rate reacting computational fluid dynamics of the experimental configuration indicates that relatively long duration argon relaxation times lead to a highly nonequilibrium shock layer in which a significant Hall effect arises. This is important because it is expected that future flight vehicles using magnetohydrodynamic aerobraking technology will also be operated at flight conditions where Hall effect is strong. Shock stand-off was measured using high-speed luminosity imaging for various magnetic and nonmagnetic model configurations. Experimental results in this paper support previous numerical studies that found that only an electrically insulated model surface can generate a significant magnetohydrodynamic interaction when Hall effect is strong.

Моделювання взаємодії космічних апаратів з іоносферною розрідженою плазмою

Principles of simulation of the physical-chemical and electromagnetic interaction of a spacecraft with the near-satellite environment and principles of probe diagnostics of rarefied plasma flows onboard a spacecraft are stated. Equivalence criteria are formulated for the interaction of a spacecraft with the near-satellite environment and hypersonic rarefied plasma flows on dedicated setups, in particular on the plasmaelectrodynamic setup of the Institute of Technical Mechanics of the National Academy of Sciences of Ukraine and the State Space Agency of Ukraine, which has the status of the National Patrimony of Ukraine. The features of spacecraft interaction with the near-satellite environment were studied along the following three lines: - degradation of the materials and performance characteristics of spacecraft components in a long-term orbital service: - magnetohydrodynamic interaction of a spacecraft with hypersonic rarefied plasma flows; - probe diagnostic of rarefied plasma flows onboard a spacecraft. Along the first line, a calculation-and-experiment procedure was developed to evaluate the power decrease of spacecraft silicon solar batteries under long-term (~ 10 years) exposure to the space factors and the near-satellite environment in circular orbits. Principles of accelerated life tests for the resistance of spacecraft polymer materials to long-term exposure to atomic oxygen flows and vacuum ultraviolet radiation were developed. Simultaneous exposure of polymers to atomic oxygen and vacuum ultraviolet radiation results in the synergic effect of mass loss by materials that contain a monomer of the (CH)n group. Along the second line, models were formulated for magnetohydrodynamic interaction in the magnetized spacecraft – ionospheric plasma system. It was shown that the interaction of a ?0,8 – 1.5 T magnetic field of a space debris object (in particular, a spent spacecraft) with the ionospheric plasma produces an electromagnetic drag force sufficient for removing it to a low orbit followed by its burn-up in the dense atmosphere. Along the third line, procedures were developed for ionospheric plasma probe diagnostics using onboard instrumentation that includes mutually orthogonal cylindrical electrical probes and a two-channel neutral-particle detector. It was shown that this instrumentation with the use of proprietary output signal interpretation algorithms and procedures allows one to locate sources of space-time disturbances in inospheric plasma parameters caused by natural and technogeneous catastrophic phenomena on the subsatellite track.

Expansion Tube Experiments of Magnetohydrodynamic Aerobraking for Superorbital Earth Reentry

A set of magnetohydrodynamic (MHD) aerobraking experiments was conducted with the aim of simulating the Earth reentry environment for Mars return trajectories, and to study the effects of MHD flow control on the ionizing shock layer surrounding a planetary entry vehicle. The X2 expansion tube of the University of Queensland was used, which could provide realistic flowfield boundary conditions, where ionization is spontaneously generated within the shock layer as in true flight and the freestream is nonconducting. Suitable flow conditions providing strong MHD interaction at superorbital Earth reentry velocities were developed. Steel ball and neodymium permanent magnet models were tested, both uncoated and coated with electrically insulating high-temperature epoxy. Shock-layer high-speed imaging showed a significant increase in shock standoff distance for the magnetic models. The experimental shock standoff results generally agreed well with analytical and numerical shock standoff predictions. These experiments demonstrate that a strong MHD interaction can be generated for a Mars return trajectory with moderate magnetic field strengths. Furthermore, they provide a promising framework for future MHD aerobraking experiments to investigate MHD drag force and heat-flux mitigation.

Flow Control Mechanism Based on Magnetic Induced Vortex for Reentry Vehicles

A novel magnetohydrodynamic (MHD) flow control mechanism based on the magnetic induced vortex is proposed to improve the thermal protection performance and aerodynamic performance of reentry vehicles. The magnetic field based on the polygonal coil grid is designed to obtain different vortex forms. Five Lorentz force models are constructed to reveal the MHD interaction mechanisms of the magnetic induced vortex. By numerically solving the low-magneto-Reynolds-number equations, the flowfields of the two-dimensional cylinder and three-dimensional sphere with the different vortex forms are obtained. Two vortex forms are found in the side and head regions of the cylinder, respectively. Under the influence of the vortexes, the high heat flux, which may be higher than the original one, is restricted in the regions near the coil centers in both the two- and three-dimensional cases. About 40% mitigation of total wall heat flux and nearly 60% drag increment are observed in the three-dimensional cases. By changing the switch states of the coils in the different regions, an additional aerodynamic force can be generated for the adjustment of flight attitude and trajectory. Hence, the magnetic induced vortex provides an effective MHD flow control method for reentry vehicles.

The onset of instabilities and finite amplitude waves in a model of aluminum reduction cells with nonuniform cathode current

In aluminum reduction cells, the electric current density at the cathode is seldom uniform. This may be due to a variety of reasons. One of the reasons is that a mass of undissolved alumina may get enrobed by the cryolitic bath, and this mix freezes due to the decrease in temperature below the liquidus point. Thus, an electrically resistive solid layer (“mud”) is formed at a part of the cathode. This leads to horizontal electric currents in the liquid aluminum layer, and their magnetohydrodynamic (MHD) interaction with the vertical magnetic field induces a rotating flow of aluminum. This may cause undesirable MHD instabilities. A quasi-two-dimensional model for the laboratory facility has been presented. The results show that the dominating feature of the flow is a depression of the free surface of the liquid metal above the mud spot. This is due to strong rotation of the liquid metal around the mud spot, which causes the centrifugal force. Other effects may include superimposed conventional MHD instability, which manifests itself in a rotating interface, modulated waves, reflection of the waves from the corners of the domain, sloshing, etc. It has been shown that small mud spots do not affect the cell stability, while the large ones may cause such deep depressions that the centrifugal force completely removes the liquid metal above the spot.

Expansion Tube Test Flow Design for Magnetohydrodynamic Aerobraking

This paper explores the operating envelope for the University of Queensland’s free-piston driven X2 expansion tube to determine if flow conditions can be produced that generate a significant magnetohydrodynamic interaction. Numerical calculations are presented to demonstrate the existence of viable operating conditions to study magnetohydrodynamics. Argon is selected as the test gas due to its simple chemistry and low ionization enthalpy. A candidate flow condition is selected for detailed analysis and experimental validation. Finite-rate reacting argon numerical simulations indicate that relatively short shock-layer length scales for the models tested in X2 limit the degree of argon ionization that is generated. However, a strong interaction remains available, and use of a larger facility can fully mitigate this issue. It is shown that expansion tubes are capable of generating the required flowfield for these experiments, and important considerations for design of suitable test flows are identified.

Hypersonic flow control of shock wave/turbulent boundary layer interactions using magnetohydrodynamic plasma actuators

The effect of magnetohydrodynamic (MHD) plasma actuators on the control of hypersonic shock wave/turbulent boundary layer interactions is investigated here using Reynolds-averaged Navier-Stokes calculations with low magnetic Reynolds number approximation. A Mach 5 oblique shock/turbulent boundary layer interaction was adopted as the basic configuration in this numerical study in order to assess the effects of flow control using different combinations of magnetic field and plasma. Results show that just the thermal effect of plasma under experimental actuator parameters has no significant impact on the flow field and can therefore be neglected. On the basis of the relative position of control area and separation point, MHD control can be divided into four types and so effects and mechanisms might be different. Amongst these, D-type control leads to the largest reduction in separation length using magnetically-accelerated plasma inside an isobaric dead-air region. A novel parameter for predicting the shock wave/turbulent boundary layer interaction control based on Lorentz force acceleration is then proposed and the controllability of MHD plasma actuators under different MHD interaction parameters is studied. The results of this study will be insightful for the further design of MHD control in hypersonic vehicle inlets.

Analytic model of a plane resistive magnetohydrodynamic shock with Hall effect

In the present work, our formerly published analytical model of resistive magnetohydrodynamic (MHD) shock without Hall effect has been extended to include the Hall effect. Original jump conditions at a plane oblique shock, analogous to the Rankine–Hugoniot formulas, with a moderately resistive air plasma downstream are derived. Viscous and Ohmic dissipations are neglected, but the jump of isentropic exponent, caused by molecular dissociations behind the shock, is also included in the model. Then, for an application to atmospheric entry problems, a shock fitting procedure with realistic geometrical configurations and ambient conditions at two altitudes is worked out by the coupling of these MHD jumps with thermodynamic correlations at equilibrium and an electrical conductivity model. Fundamental features put into evidence are the reduction and saturation of the MHD interaction by the Hall effect as the magnetic field increases, and the crucial role played by the ion slip factor in the phenomenon. Paradoxically, the Hall effect arises because of the dominance of the magnetic field over collisions, and eventually it counters the MHD interaction. The validity of the assumption of plasma equilibrium and possible validation experiments for the flight conditions considered are also discussed.

Nonlinear dynamical magnetosonic wave interactions and collisions in magnetized plasma

The one-dimensional nonlinear dynamical wave interactions in a system of quasineutral two-fluid plasma in a constant magnetic field are investigated. The existence of the travelling wave solutions is discussed. The modulation stability of linear waves and the modulation instability of weakly nonlinear waves are presented. Both suggest that the Korteweg-de Vries (KdV) system is modulationally stable. Besides, the wave interactions including the periodic wave interaction and the solitary wave interaction are captured and presented. It is shown that these interacting waves alternately exchange their energy during propagation. The Fourier spectrum analysis is used to depict the energy transformation between the primary and harmonic waves. It is known that the wave interactions in magnetized plasma play an important role in various processes of heating and energy transportation in space and astrophysical plasma. However, few researchers have considered such magnetohydrodynamic (MHD) wave interactions in plasma. It is expected that this work can provide additional insight into understanding of behaviors of MHD wave interactions.

Numerical and Experimental Simulation of Magnetohydrodynamic Interaction in a Hypersonic Flow of a Blunt Body

This paper describes results of an experimental and numerical study of a magnetohydrodynamic (MHD) method for controlling a hypersonic (M = 6) air flow in which a launched device of typical configuration is located. The experiments are carried out using an MHD rig based on a shock tube. The flow in front of the body is ionized using an electric discharge in an external magnetic field with an induction B = 0.80–1.58 T. Conditions corresponding to the experimental conditions are numerically simulated using the Reynolds-average steady Navier-Stokes equations. The MHD interaction region is simulated by isolating a zone in front of the blunt part of the model with given force and heat sources. It is shown that, as a result of strong MHD interaction, the bow shock moves away from the model surface and the heat flux to the body decreases with a value of the Stuart number S = 0.1–0.3.