Upstream Interface Research Articles

Effects of disturbed transmitted shock and interface coupling on heavy gas layer evolution

Development of a heavy gas layer with an upstream single-mode interface and a downstream planar interface accelerated by a shock wave is investigated. By considering the amplitude variation of the transmitted shock and interface coupling, a modified model is established, which provides good predictions on the linear growth rates of the perturbations on both interfaces. Through the model, the perturbation growth of the downstream interface can be frozen by choosing a suitable layer width. In such a shocked layer, interface coupling has an ignorable effect on the nonlinear evolution of the upstream interface but significantly changes the nonlinear evolution of the downstream interface. A new dimensionless approach is proposed to scale the nonlinear growth of the middle spike on the downstream interface. Finally, through modal analysis, we find that the pressure perturbations rather than interface coupling result in the formation of the small spike on the bubble head of the downstream interface.

Numerical Simulation of the Interaction between a Planar Shock Wave and a Cylindrical Bubble

Three-dimensional (3D) computational fluid dynamics (CFD) simulations have been carried out to investigate the complex interaction of a planar shock wave (Ma = 1.22) with a cylindrical bubble. The unsteady Reynolds-averaged Navier–Stokes (URANS) approach with a level set coupled with volume of fluid (LSVOF) method has been applied in the present study. The predicted velocities of refracted wave, transmitted wave, upstream interface, downstream interface, jet, and vortex filaments are in very good agreement with the experimental data. The predicted non-dimensional bubble and vortex velocities also have great concordance with the experimental data compared with a simple model of shock-induced Rayleigh–Taylor instability (i.e., Richtmyer–Meshkov instability) and other theoretical models. The simulated changes in the bubble shape and size (length and width) against time agree very well with the experimental results. Comprehensive flow analysis has shown the shock–bubble interaction (SBI) process clearly from the onset of bubble compression up to the formation of vortex filaments, especially elucidating the mechanism on the air–jet formation and its development. It is demonstrated for the first time that turbulence is generated at the early phase of the shock cylindrical bubble interaction process, with the maximum turbulence intensity reaching about 20% around the vortex filament regions at the later phase of the interaction process.

Hystereses in flow-induced compression of a poroelastic hydrogel.

We investigate theoretically the one-dimensional compression of a hydrogel layer by a uniform fluid flow normal to the gel surface. The flow is driven by a pressure drop across the gel layer, which is modeled as a poroelastic medium. The novelty comes from considering, for the first time, the impact of interfacial permeability and compression. This leads to several new features for the flow and gel compression. As the pressure simultaneously drives the Darcy flow through the pores and compresses the gel, the flux-pressure relationship may become non-monotonic. Most interestingly, we discover two types of hysteresis when the pressure or the flux is controlled, which are also confirmed by transient numerical simulations. The first type of hysteresis stems from the interplay between the gel compression at the upstream interface and that in the bulk of the gel, and would not be predicted by models that ignore the interfacial compression. The second type hinges on strain-hardening in the gel that maintains a non-vanishing permeability at high pressure. Finally, we suggest experimental setups and conditions to seek such hystereses in real gels.

An improved void fraction prediction model for gas-liquid two-phase flows in pipeline-riser systems

This paper introduces the application of void fraction prediction models (25 models total) from a simple horizontal pipe to a complex, real pipeline. The flow mechanism in the pipeline-riser system is explained based on the upstream phase interface and differential pressure in the downstream riser. The transition boundaries of “stratified to intermittent flow” and “stratified smooth to stratified wavy flow” in the horizontal section were predicted well by the models based on simple pipes. Electrical capacitance volume tomography was used to obtain the upstream void fraction just before the downstream gas-liquid eruption, α1, or during multiple cycles, α2. The difference between α1 and α2 are ranging between −10 % and 5 %. Finally, an improved correlation is proposed based on the model found to be best (Lockhart and Martinelli, with error values (root mean square error (RMSE) and mean absolute percentage error (MAPE)) of about 12 % and 18 %); the corresponding error levels (RMSE and MAPE) amount roughly to 5 % and 10 %, respectively. The improved model also delivers a good prediction for α1 when separating in two flow regimes. Overall, the finally proposed correlation reads and is found superior in terms of accuracy to all previously published correlations.

Fully conservative hydraulic jumps and solibores in two-layer Boussinesq fluids

We consider a special type of hydraulic jumps (internal bores) which, in the vertically bounded system of two immiscible fluids with slightly different densities, conserve not only the mass and impulse but also the circulation and energy. This is possible only at specific combinations of the upstream and downstream states. Two such combinations are identified with arbitrary upstream and downstream interface heights. The first has a cross symmetry between the interface height and shear on both sides of the jump. This symmetry, which is due to the invariance of the two-layer shallow-water system with swapping the interface height and shear, ensures the automatic conservation of the impulse and energy as well as the continuity of characteristic velocities across the jump. The speed at which such jumps propagate is uniquely defined by the conservation of the mass and circulation. The other possibility is a marginally stable shear flow which can have fully conservative jumps with discontinuous characteristic velocities. Both types of conservative jumps are shown to represent a long-wave approximation to the so-called solibores which appear as smooth permanent-shape solutions in a weakly non-hydrostatic model. A new analytical solution for solibores is obtained and found to agree very well with the previous DNS results for partial-depth lock release flow. The finding that certain large-amplitude hydraulic jumps can be fully conservative, while most are not such even in the inviscid approximation, points toward the wave dispersion as a primary mechanism behind the lossy nature of internal bores.

On the shock-driven hydrodynamic instability in square and rectangular light gas bubbles: A comparative study from numerical simulations

A comparative investigation of the hydrodynamic instability development on the shock-driven square and rectangular light gas bubbles is carried out numerically. In contrast to the square bubble, both horizontally and vertically aligned rectangular bubbles with different aspect ratios are taken into consideration, highlighting the impacts of aspect ratios on interface morphology, vorticity production, and bubble deformation. Two-dimensional compressible Euler equations for two-component gas flows are simulated with a high-order modal discontinuous Galerkin solver. The results show that the aspect ratio of rectangular bubbles has a considerable impact on the evolution of interface morphology in comparison with a square bubble. In horizontal-aligned rectangular bubbles, two secondary vortex rings connected to the primary vortex ring are produced by raising the aspect ratio. While in vertical-aligned rectangular bubbles, two re-entrant jets are seen close to the top and bottom boundaries of the upstream interface with increasing aspect ratio. The baroclinic vorticity generation affects the deformation of the bubble interface and accelerates the turbulent mixing. Notably, the complexity of the vorticity field keeps growing as the aspect ratio does in horizontal-aligned rectangular bubbles, and the trends are reversed in the vertical-aligned rectangular bubbles. Further, these aspect ratio effects also lead to the different mechanisms of the interface characteristics, including the upstream and downstream distances, width, and height. Finally, the temporal evolution of spatially integrated fields, including average vorticity, vorticity production terms, and enstrophy are analyzed in depth to investigate the impact of aspect ratio on the flow structure.

On the irregular jet formation of shock-accelerated spherical heavy gas bubbles

The behaviors of shock-accelerated heavy gas bubbles are numerically investigated, focusing on clarifying the forming mechanisms of the bubble jets in different types. The present study categorizes heavy bubble jets into two types, regular jets, and irregular jets. The present shock-accelerated multi-component flows are simulated by solving inviscid compressible Euler equations. An upwind characteristic space-time conservation element solution element scheme is adopted, and a five-equation model is used to treat the gas interface. Bubbles of R22, SF6, and Kr in ambient N2 and air are examined, and the incident shock Mach numbers are 1.1 and 1.23. The numerical results demonstrate that the bubble jet formation and its shape are very sensitive to the test gas species and incident shock strength. It is found that the tiny upstream jet formed in the single-shocked SF6/air scenario results from a very small Mach stem impingement onto the bubble upstream interface, the type II shock-shock interaction features the flow mechanism. While the large upstream jet formed in the re-shock SF6/air scenario is a combined result of the re-shock convergence and later vortex stretching. For the complex Kr/air scenario, the upstream jet results from the vorticity-induced inward jet stretching, and the downstream hollow jet results from the slip line guided tip extension. The measurements of bubble volumes, gas mixings, and material line lengths suggest that, although the jet formation greatly changes the bubble morphology, it makes a minor contribution to the bubble overall integral properties.

Design optimization for Richtmyer–Meshkov instability suppression at shock-compressed material interfaces

The Richtmyer–Meshkov instability (RMI) is a phenomenon that occurs at the interface of two substances of different densities due to an impulsive acceleration, such as a shock wave passing through this interface. Under these conditions, the instability can be seen as interface perturbations begin to grow into narrow jets or spikes of one substance that propagate into the other. In some cases, this interface may involve an elastic–plastic material, which can play a significant role in the development and behavior of the RMI. The ability to effectively control RMI jetting and spike growth is one major limiting factor in technological challenges, such as inertial confinement fusion, that involve using high-pressure shock waves to implode a fuel target. The propagation of RMI growth can lead to increased asymmetry in this implosion process and significantly reduce the obtained energy yield. We use hydrodynamics simulations of impactor shock-compression experiments and methods based in design optimization to suppress RMI spike growth by altering the geometry and other properties of a shock-compressed elastic–plastic material target that shares an interface with atmospheric air. These hydrodynamics simulations use an arbitrary Lagrangian–Eulerian method with a high-order finite element approach. Our results demonstrate that RMI suppression can be achieved by intentionally creating a separate upstream interface instability to counteract the growth of long narrow RMI spikes at an interface with initial perturbations.

Deformation behavior of liquid droplet in shock-induced atomization

The purpose of this study is to clarify the deformation behavior characteristics of a single droplet in the high Weber number region corresponding to catastrophic breakup, depending on the Weber number, and show the relationship between the spread of fragments and their initial deformation behavior. Accordingly, we investigated waves generated from the droplet surface by photographing the deformation behavior of the droplet with high spatio-temporal resolution and the correlations between the Weber number and height and thickness of the parent droplet, center-of-mass movement, and movement of the leading and trailing edges. The results show no significant relationship between the spread of the fragment and its initial deformation behavior. We also measured the wavelength of the wave pattern at the upstream interface of the droplet during a catastrophic breakup. As a result, a relationship between the wavelength of the upstream interface of the droplet and the Weber number was found.

Numerical analysis of shock interaction with a spherical bubble

Two-dimensional and three-dimensional computational fluid dynamics studies of a spherical bubble impacted by a supersonic shock wave (Mach 1.25) have been performed to fully understand the complex process involved in shock–bubble interaction (SBI). The unsteady Reynolds-averaged Navier–Stokes computational approach with a coupled level set and volume of fluid method has been employed in the present study. The predicted velocities of refracted wave, transmitted wave, upstream interface, downstream interface, jet, and vortex ring agree very well with the relevant available experimental data. The predicted non-dimensional bubble and vortex velocities are also in much better agreement with the experiment data than values computed from a simple model of shock-induced Rayleigh–Taylor instability (the Richtmyer–Meshkov instability). Comprehensive flow visualization has been presented and analyzed to elucidate the SBI process from the beginning of bubble compression (continuous reflection and refraction of the acoustic wave fronts as well as the location of the incident, refracted and transmitted waves at the bubble compression stage) up to the formation of vortex rings as well as the production and distribution of vorticity. Furthermore, it is demonstrated that turbulence is generated with some small flow structures formed and more intensive mixing, i.e., turbulent mixing of helium with air starts to develop at the later stage of SBI.

Evolution of shock-accelerated double-layer gas cylinder

Developments of the shock-accelerated concentric double-layer gas cylinder with an air cylinder embedded into an SF6 cylinder have been experimentally investigated for the first time. The double-layer gas cylinder is created by the soap film technique. Effects of the inner cylinder on the evolution of the outer one are highlighted by changing the radius ratio, i.e., a ratio of the inner radius to the outer one. The flow features show that the two cylinders evolve independently at the early stage, whereas they couple together at the late stage. The presence of the inner cylinder changes the behavior of shock movements, and a vortex pair instead of an outward jet is generated at the downstream interface. The scale of the vortex pair is proportional to the initial radius ratio. The rarefaction waves generated from the upstream interface of the inner cylinder accelerate the upstream interface of the outer cylinder earlier than the single-layer SF6 cylinder. Depending on the radius ratio, the acceleration induced by the rarefaction wave impact either prolongs or shortens the linear phase of the upstream interface movement. The waves' effect results in the failure of the nonlinear model in predicting the upstream interface movement. For the outer cylinder, its movements in both the streamwise and spanwise directions are promoted by the inner one. For the inner cylinder, its movements in the streamwise and spanwise directions are, respectively, inhibited and promoted by the outer one. As the radius ratio increases, the effect of promotion or prohibition is stronger.

Steady-state growth of an interfacial crack by corrosion

The Wiener–Hopf technique is used to obtain a 2D steady-state solution for the progressive conversion of a pristine interface into a corroded interface between two dissimilar solids. The interface is of infinite extent, and comprises a semi-infinite pristine portion and a semi-infinite corroded portion. Fickian diffusion of the active species (solute) occurs in the upper half-space, with no diffusion in the lower half-space. Corrosion occurs by chemical reaction between the solute and the top surface of the lower half-space, and the path of solute diffusion involves 3 stages. The solute (i) leaves a solute-rich zone of disbonded and previously corroded interface, (ii) enters into and diffuses through the upper half-space, and (iii) leaves the upper half-space and enters the upstream pristine interface where it reacts with the surface of the lower half-space to produce the corrosion product. A steady state is established: the corrosion front moves at a constant velocity V which is dictated by the critical value of accumulated solute on the interface that is needed to form corrosion product and disbond the interface. The reaction zone directly ahead of the corrosion front has a characteristic length that depends upon the diffusion parameters and front velocity V. An asymptotic solution by the Wiener–Hopf analysis is obtained for the diffusion problem at large V. Scaling laws emerge and support the predictions of a much simpler 1D physical model.

Experimental investigation of internal two-phase flow structures and dynamics of quasi-stable sheet cavitation by fast synchrotron x-ray imaging

The quasi-stable sheet cavitation produced in a small Venturi channel is investigated using a fast synchrotron x-ray imaging technique aided with conventional high speed photography. The use of x rays instead of visible light solves cavitation opacity related issues, and x-ray phase contrast-based edge enhancement enables high-definition visualization of the internal two-phase morphology. The simultaneous acquisition of time-resolved velocity and void fraction fields through post-processing of the recorded x-ray images reveals, for the first time, the complex diphasic flow structures inside the sheet cavity, which is essentially divided into six characteristic parts. Distinct from the current mainstream view, the globally steady sheet cavitation is found to be characterized by a weak but constantly existing re-entrant flow that can penetrate the entire cavity. The turbulent velocity fluctuations inside the sheet cavity are also investigated. The turbulence level in the reverse flow region is observed to be as low as in the outer main flow, demonstrating the relatively steady status of the re-entrant flow. Unlike the streamwise and cross-stream fluctuations, the shear stress appears to be weakly correlated with the velocity gradient. The collapse of the vapor phase and the vaporization at the upstream cavity interface are found to be the primary causes of shear stress intensification.

Coupling effect on shocked double-gas cylinder evolution

Interaction of a weak planar shock wave with double heavy gas cylinders has been investigated, focusing on coupling effect on the post-shock flow. In experiments, the ideal two-dimensional discontinuous double heavy gas cylinders with controllable initial conditions are generated by soap film technique, and the shocked flow is captured by a high-speed schlieren photography. Two different initial center spacings of cylinders are considered to highlight the coupling effect. As the center spacing reduces, the coupling effect occurs earlier and becomes more prominent. The coupling effect greatly promotes the inner vortex motions near the symmetry axis relative to the outer ones, resulting in the formation of the mushroom and twisted jets. The fusion of the inner vortices completely differs from the observation in previous experimental work in which the inner vortices separate from each other. Quantitatively, the motion of the upstream interface in streamwise direction is obtained, and can be predicted by a nonlinear model considering the coupling effect. Besides, a vortex model is proposed based on the induction equation of point vortex, and the effect of the mutual interferences among vortices on the vortex motions can be well evaluated.

RFID Enabled Framework for Substation Maintenance Management

Objectives: Effective substation maintenance management based on low cost and reliable Radio Frequency Identification (RFID) enabled implementation framework. Methods/Statistical Analysis: Economical operation of substation by minimizing the equipment maintenance cost is the prime concern for all the power distribution utilities. Number of maintenance management strategies has been developed for optimizing the substation equipment maintenance cost. Effectiveness of these optimized maintenance strategies lies on the actual implementation in the field. Currently equipment maintenance activities are carried out with off-line association with equipment. Also, equipment maintenance data is acquired and populated manually into host computer which is running maintenance cost optimization applications. Inherently manual process suffers from various drawbacks and results in poor maintenance management. RFID based technology along with embedded system is identified for making the above off-line process into an on-line process with data integrity. Findings: Present paper proposes a Radio Frequency Identification (RFID) enabled implementation framework to perform the maintenance with on-line association with equipment. This allows on-line access with the equipment and eliminates the manual process of acquiring data from equipment at the substation level. Also, ensures the on-line update of pre-maintenance and postmaintenance information of equipment in the Computerised Maintenance Management System (CMMS). Conventional RFID readers which are based on multi-purpose hand-held computers are driven by high level operating systems and programming languages. Due to high level system software on handheld readers, the network latency increases and data refresh rate decreases. This paper proposes a low cost microcontroller based RFID reader with up-stream data interface using low level network programming to address the above issues. Host computer data interface is implemented using a TCP/IP protocol which assures the data integrity. The low level programming at the host computer for network communication minimizes the network latency in the data transfer and improves the data refresh rate. Maintenance process with RFID framework is designed and explained. Application/Improvements: Maintenance management strategies can be implemented effectively using the proposed RFID enabled framework with customized RLU along with low level network interface to CMMS. Present implementation based on Ethernet interface over TCP/IP can be extended seamlessly for wireless (Wi-Fi) as well. Keywords: JSP, Maintenance, RFID, Substation, TCP/IP

Interaction of planar shock wave with three-dimensional heavy cylindrical bubble

Interactions of a planar shock wave with two-dimensional (2D), three-dimensional (3D) concave, and 3D convex SF6 cylindrical bubbles surrounded by air are studied both experimentally and numerically. The effects of initial interface curvature on the bubble deformation and wave propagation are highlighted. The cylindrical bubbles are generated by a wire-restriction method based on the soap-film technique, and their shapes are well controlled by adjusting the pressure difference across the interface. The high-speed schlieren results demonstrate that the evolving interfaces develop more symmetrically than previous studies as they are free of holder and fewer disturbance waves are generated. Typical evolution processes of the 2D bubble such as the jet formation and vortex pair formation are clearly captured. Compared with the 2D case, the oppositely (identically) signed principal curvatures of the concave (convex) boundary produce more complicated high pressure fields and 3D additional baroclinic vorticity. For 3D cases, the numerical results show that the wave patterns in the symmetry or boundary slice are distinct from the 2D case owing to the 3D movement of the generated waves, and the jet structure presents an evident three dimensionality. In particular, for the concave bubble, a certain slice between the boundary and symmetry slices presents the fastest-developing jet, while for the convex case the fastest jet emerges at the boundary slice. The upstream interface along the symmetry slice of the concave (convex) bubble moves faster (slower) than that of the 2D case, which is reasonably predicted by a 3D theoretical model.

Modeling of Solid Conveying Pressure Throughput Behavior of Single Screw Smooth Barrel Extruders under Consideration of Backpressure and High Screw Speeds

AbstractThe task of the solid conveying section is to collect the entering material and transfer it to the melt dominated sections. Therefore, its upstream interface is the hopper and its downstream interface is the section in which the first melting occurs. Beneath the hopper opening, the screw rotation collects and conveys the material forward. It is hereby assumed that the friction forces among the particles are higher than the transferring forces on the screw and barrel. For that reason commonly known models for describing the solid conveying in single screw extruders assume that the screw channel is always completely filled so that a plug flow occurs. At high screw speeds, however, these assumptions are no longer valid. To analyze and mathematically describe the solid conveying behavior at screw speeds up to 2000 rpm, simulations based on the Discrete Element Method have been executed in previous investigations. Based on this, a model for describing the solid conveying behavior was developed which enables a variation of general screw and hopper geometry parameters but neglects the backpressure that inhibits the solid movement. For that reason, further investigations based on the Discrete Element Method are presented in this paper, which enable a consideration of the backpressure and pressure build-up in the feeding zone. Astonishingly, at high screw speeds a low filling degree in the screw channel was observed which did not fulfill the expectations of an always fully filled channel due to a backpressure forced particle backlog. Based on the investigations, a mathematical model has been developed which now fully comprehends the effects occurring in the solid conveying section. The conducted simulations were subsequently validated by experimental investigations. Therefore, a test bench was designed which enables solid conveying analysis with adjustable backpressures. The results indicate a good agreement with the formulated model which now enables the calculation of solid conveying zones with consideration of the pressure build-up and filling degrees.

Development of a Methodology for Interface Boundary Selection in the Multiscale Road Tunnel Fire Simulations

The simulation of large complex dynamical systems such as a fire in road tunnels is necessary but costly. Therefore, there is a crucial need to design efficient models. Coupling of computational fluid dynamics (CFD) models and 1D network modeling simulations of a fire event, a multiscale method, can be a useful tool to increase the computational efficiency while the accuracy of simulations is maintained. The boundary between a CFD model (near field) and a 1D model (far field) plays a key role in the accuracy of simulations of large systems. The research presented in this paper develops a novel methodology to select the interface boundary between the 3D CFD model and a 1D model in the multiscale simulation of vehicle fire events in a tunnel. The development of the methodology is based on the physics of the fluid structure, turbulent kinetic energy of the dynamical system, and the vortex dynamics. The methodology was applied to a tunnel with 73.73 m2 cross section and 960 m in length. Three different vehicle fire scenarios were investigated based on two different heat reslease rates (10 MW and 30 MW) and two different inlet velocities (1.5 m/s and 5 m/s). all parameters upstream and downstream of the fire source in all scenarios were investigated at t = 900 s. The effect of changes in heat release rate (HRR) and air velocity on the selection of an interface boundary was investigated. The ratio between maximum longitudinal and transversal velocities was within a range of 10 to 20 in the quasi-1D region downstream of the fire source. The selected downstream interface boundary was 12Dh m downstream of the fire for the simulations. The upstream interface boundary was selected at 0.5 Dh m upstream the tip of the object when the velocity was greater than equal to the Vc. In the simulations with backlayering (V < Vc), the interface boundary was selected 10 m further from the tip of the backlayering (1.2 Dh). An indirect coupling strategy was utilized to couple CFD models to 1D models at the selected interface boundary; then, the coupled models results were compared to the full CFD model results. The calculated error between CFD and coupled models for mean temperature and velocity at different cross sections were calculated at less than 5%. The findings were used to recommend a modification to the selection of interface boundary in multiscale fire simulations in the road tunnels and more complex geometries such as mines.

Effect of Gradation of Bed Material on Local Scour Depth

The paper presents a study on local scour with respect to bed material gradation, flow depth and the Froude number. In the study, bed materials collected from five different rivers were used separately for four different shapes of the obstructions. The water discharge was also varied for each run. The experimental results obtained, reveal the dependence of local scour on the overall bed material gradation, and shape of the obstruction, especially the upstream interface. The models developed on basis of the experimental findings for different shapes are more realistic than the widely adopted criteria which mainly consider only effective size, d50 of the bed material, ignoring the other gradation parameters. Moreover, it was found that the obstruction shape also affects the scour phenomenon considerably.

Numerical investigations of interactions between shock waves and triangular cylinders in magnetic field

Magnetohydrodynamic (MHD) equations are solved by using the CTU+CT (corner transport upwind + constrained transport) algorithm which guarantees the divergence-free constraint on the magnetic field. The interactions between shock wave and heavy or light triangular cylinder are investigated in detail in the cases with and without magnetic field. In the cases of hydrodynamic (B=0 T) and MHD (B=0.01 T), the numerical results indicate that heavy and light triangular cylinders have quite different wave patterns and jet structures after being impacted by a planar incident shock wave. Specifically, a regular refraction and downstream R22 jet are formed in the heavy case, whereas an irregular refraction and upstream air jet are generated in the light case. In the hydrodynamic case, the Richtmyer-Meshkov (R-M) instability and Kelvin-Helmholtz (K-H) instability are induced by the incident shock wave. Hereafter, both heavy and light density interfaces begin to roll up with a series of interfacial vortex sequences. In addition, a main vortex ring is formed in the heavy case, while a vortex dipole passing through the downstream interface is generated in the light case. In the MHD case, both heavy and light density interfaces remain smooth and interfacial vortex sequences vanish. Furthermore, the main vortex ring formed in the heavy cases and the vortex dipole generated in the light cases disappear. Moreover, in the presence of a magnetic field, a detailed investigation demonstrates that Lorentz forces give rise to the transport of baroclinic vorticities to the Alfvn waves. As a consequence, the deposition of interfacial vorticities decreases and the rolling-up of interfaces is suppressed. In the end, the vorticities are transformed into two vortex sheets travelling away from the density interfaces, and the R-M instability and K-H instability are well controlled. The quantitative investigations reveal that for both heavy and light triangular cylinders, magnetic field can accelerate the upstream interface and decelerate the downstream interface, especially for the light triangular cylinder.