Numerical Simulation Of Interaction Research Articles

Numerical Simulation of Interaction between Kulluk Platform and Laminar Ice

Over the years, the development of the Arctic region has been increasingly emphasized, and the research and development of offshore platforms has become a research hotspot for many countries. Among them, all kinds of platform equipment used in the polar region must consider the special conditions when operating in extreme environments. For the floating ice-resistant marine platforms, the calculation of ice load is of considerable importance and value for the applicability and reliability design. In this article, the Kulluk platform has been chosen for the study. The interactions between the structure and the sea ice, such as collision and extrusion, are numerically simulated through the finite element method. In this paper we will explain how to calculate the ice loads acting on the floating platform and the specific loads. By setting the real scale in the program, the maximum correspondence with the real situation can be achieved. Subsequently, the numerical simulation values were analyzed and compared with the actual situation and empirical formulas to verify the reliability of the numerical simulation. The applicability of the Kulluk platform model to the problem of interaction with the leveling ice has been validated.

Numerical Investigation of the Effects of Chemical Species and Chemical Kinetic Mechanisms on Laminar Premixed Flame-Acoustic Wave Interactions

Numerical simulation of interactions between acoustic waves and flames is of utmost importance in thermo-acoustic instability research. In this study, interactions between a one-dimensional Methane-Air laminar premixed flame and acoustic waves with a frequency of 50 to 50000 Hz are simulated by simultaneously solving the equations for energy conservation, chemical species transport, state and continuity in one-dimensional space. By assuming that the flame thickness is smaller than the acoustic wavelength, the spatial pressure fluctuations can be neglected and the flame experiences only a time-varying acoustic pressure. The GRI mechanisms, as well as their reduced mechanisms, are considered to obtain results for steady flames without acoustic waves, and the interaction of unsteady flames with acoustic waves. Results show that the total heat-release-rate fluctuations for the flame is affected by increasing the frequency of the acoustic wave. An increase in frequency first increases the total heat released, and then decreases it. The obtained results are in good agreement with those of other researchers. Furthermore, at the presence of acoustic waves, various chemical species can affect the total heat-release-rate fluctuations. With Rayleigh's instability criterion, it can be shown that H2O, CO2 and O2 are the main species to the fluctuations of the total heat release rate and lead to flame instability. Results show that heat-release-rate of H2O specie is the most important on the total heat-release-rate. Therefore, for the flame-acoustic waves interaction problem, the best mechanism is the one that could predict the concentration of H2O more precisely.

Simulation of debris flow-barrier interaction using the smoothed particle hydrodynamics and coupled Eulerian Lagrangian methods

Debris flow events occur when fine soils and sediments are mixed with water, transporting coarse objects such as boulders and woody vegetation (debris) in a fast-moving down-slope flow. As such, debris flow can have catastrophic consequences for the environment, surrounding infrastructure and human life. The mitigation of damage caused by debris flow events is often addressed by rigid and flexible barriers placed in key locations to impede flow. The numerical simulation of interactions between large debris flow events and protective structures necessitates computational methods that model large deformation and flow behaviour as well as barrier performance. Although various numerical methods exist for debris flow modelling, the benefits of each method remain unclear when coupled with the analysis of protective structures. This research investigates debris flow-barrier interaction using two distinct numerical methods – the Coupled Eulerian-Lagrangian Method (CEL) and Smoothed Particle Hydrodynamics (SPH). The capabilities and limitations of each method are presented, highlighting the differences in computational cost. The results of simulations indicate preferable methods for modelling fluid-structure interaction for assessing the performance of debris flow-protective barrier structures. • The application of CEL and SPH methods in modelling of debris is investigated. • The capabilities and limitations of each method are studied. • Simulation of debris flow-boulders-barrier interactions is presented. • The effect of mesh and particle density is explained.

Numerical Simulation of Interaction between Plasma and Azithromycin Based on Molecular Dynamics

Growing attention has been paid to nonthermal plasma treatment technology and its effects on the degradation of organic matter, especially for antibiotics. However, the majority of the conducted research has focused on the experimental results. Rare attempts were made to analyze the reaction mechanism at the microscopic level. In this paper, molecular dynamics simulation and reactive forcefields were used to investigate the reaction mechanism of different plasma particle interactions with azithromycin molecules. The simulation results indicated that the degradation of azithromycin was caused by the destruction of C-H and C-C bonds, followed by the formation of C=C and C=O bonds when reacted with the active particles. It was also found that the ability of degrading azithromycin varied among the different types of active particles. The oxygen atoms had the strongest ability to decompose the azithromycin molecule, with 38.61% of the C-H bonds broken as compared with other oxygenated species. The findings from this computational simulation could provide theoretical support and guidance for subsequent practical experiments.

Estimated equivalent radiation dose at different altitudes in Earth’s atmosphere

The paper reports the results of simulation of cosmic ray proton transport through Earth’s atmosphere. The main objective of this work is to obtain characteristics of secondary particle fluxes at different altitudes and to convert them to equivalent dose values. The technique for the conversion is based on numerical simulation of interaction between the particles and an anthropomorphic phantom. The paper examines two cases, using a model source of primary proton spectra as input parameters, which correspond to both purely galactic cosmic rays and solar cosmic rays. The computational results are tabulated for the altitude range from 0 km to 11 km above sea level; the upper range value corresponds to the flight altitude of civilian airliners. These results are shown to agree well with the results obtained by other research teams.

Оценка эквивалентной дозы излучения на разных высотах атмосферы Земли

The paper reports the results of simulation of cosmic ray proton transport through Earth’s atmosphere. The main objective of this work is to obtain characteristics of secondary particle fluxes at different altitudes and to convert them to equivalent dose values. The technique for the conversion is based on numerical simulation of interaction between the particles and an anthropomorphic phantom. The paper examines two cases, using a model source of primary proton spectra as input parameters, which correspond to both purely galactic cosmic rays and solar cosmic rays. The computational results are tabulated for the altitude range from 0 km to 11 km above sea level; the upper range value corresponds to the flight altitude of civilian airliners. These results are shown to agree well with the results obtained by other research teams.

Direct numerical simulation of interaction between a stationary crossflow instability and forward-facing steps

The interaction between forward-facing steps of several heights and a pre-existing critical stationary crossflow instability of a swept-wing boundary layer is analysed. Direct numerical simulations (DNS) are performed of the incompressible three-dimensional laminar base flow and the stationary distorted flow that arise from the interaction between an imposed primary stationary crossflow perturbation and the steps. These DNS are complemented with solutions of the linear and the nonlinear parabolised stability equations, used towards identifying the influence of linearity and non-parallelism near the step. A fully stationary solution of the Navier–Stokes equations is enforced numerically, in order to isolate the mechanisms pertaining to the interaction of the stationary disturbance with the step. Results provide insight into the salient modifications of the base laminar boundary layer due to the step, and the response of the incoming crossflow instability to these changes. The fundamental spanwise Fourier mode of the disturbance field gradually lifts up as it approaches the step and passes over it. The flow environment around the step is characterised by a sudden spanwise modulation of the base-flow streamlines. Additional stationary perturbation structures are induced at the step, which manifest in the form of spanwise-aligned velocity streaks near the wall. Shortly downstream of the step, the fundamental component of the crossflow perturbation maintains a rather constant amplification for the smallest steps studied. For the largest step, however, the fundamental crossflow perturbation is stabilised significantly shortly downstream of the largest step. This surprising result is ascribed to a modulation of the kinetic energy transfer between the base flow and the fundamental perturbation field, which is brought forward as a new step interaction mechanism. Possible non-modal growth effects at the step are discussed. Furthermore, the results from DNS indicate significant amplification of the high-order harmonic crossflow components downstream of the step.

Numerical simulation of interaction between wave-driven currents and revetment on coral reefs

The stability of a revetment breakwater is vital for the safety of islands and reefs formed with reclaimed sand under the action of a complex marine environment. The interactions in wave-reef-revetment systems are complex and difficult to accurately simulate; in addition, it is difficult to describe the dynamic wave pressures distribution by empirical formula, although these parameters are important for the safety of reefs and revetments; hence, more studies are required. In this study, an investigation of the interaction between the wave-driven current on the reef flat and rear revetment breakwater is performed, and the hydrodynamic pressure on the revetment is discussed. A two-dimensional numerical model is established using the Navier–Stokes equation to explore the interaction and calculate the pressure distribution on the revetment, which is verified by an experiment designed and implemented in a wave flume. The simulation illustrates that the wave-driven current is stratified in the vertical direction, and the velocity at the surface is approximately 2–3 times that of the average value, and the maximum flow velocity can reach 13 m/s. By varying the parameters of the geomorphology of the coral reef, the results suggest that for steeper fore-reef slopes, longer reef flats, and larger relative distances, the peak value of the pressure increases consistently. The detailed and sophisticated hydrodynamic pressure distribution on the revetment is obtained, and the numerical results indicate that the fifth-order polynomial can match the regulation of pulsating pressure at the wave surface with the relative submerged water depth.

Thermodynamically Consistent Diffuse Interface Model for the Numerical Simulation of Interaction between Solid Explosive Detonation and Inert Materials

Thermodynamically Consistent Diffuse Interface Model for the Numerical Simulation of Interaction between Solid Explosive Detonation and Inert Materials

Thermodynamically Consistent Diffuse Interface Model for the Numerical Simulation of Interaction between Solid Explosive Detonation and Inert Materials

Thermodynamically Consistent Diffuse Interface Model for the Numerical Simulation of Interaction between Solid Explosive Detonation and Inert Materials

Focused Plunging Breaking Waves Impact on Pile Group in Finite Water Depth

Abstract Accuracy estimation of wave loading on cylinders in a pile group under different impact scenarios is essential for both the structural safety and cost of coastal and offshore structures. Differing from the interaction of waves with a single cylinder, less attention has been paid to pile groups under different arrangements. Numerical simulations of interactions between plunging breaking waves and pile group in finite water depth are performed using the two-phase flow model in REEF3D, an open-source computational fluid dynamics program to investigate the wave loads and flow kinematics characteristics. The Reynolds-averaged Navier–Stokes equation with the two equation k − ω turbulence model is adopted to resolve the numerical wave tank. The model is validated by comparing the numerical wave forces and free surface elevation with measurements from experiments. The computational results show fairly good agreement with experimental data. Four cases are simulated with different relative distances, numbers of cylinders, and arrangements. Results show that the wave forces on cylinders in the pile group are effected by the relative distance between cylinders. The staggered arrangement has a significant influence on the wave forces on the first and second cylinder. The interaction inside a pile group mostly happens between the neighboring cylinders. These interactions are also effected by the relative distance and the numbers of the neighboring cylinders.

Numerical Simulation of Interaction between Kr+ Ion and Rotating C60 Fullerene towards for Nanoarchitectonics of Fullerene Materials

Dynamics of charged fullerene in a surface layer of fullerite is studied under the influence of neutral or charged particles of the gas phase surrounding the fullerite material. The translational displacements of the nodes of the crystal lattice structure are determined by the equations of motion of the centers of mass of fullerenes. Central fullerene, which is described as a discrete set of sixty carbon atoms, plays a special role in the presented mathematical model. Angular oscillations and rotations of the central fullerene are described by the dynamic Euler equations. All other fullerenes have a centrally symmetric field of the potential of interaction with the surrounding atoms and molecules. In this regard, we use the hybrid discrete–continuous mathematical model with four potentials that describe the interactions between the surrounding fullerenes, smoothed fullerene and an atom, a pair of atoms, and electric charges. The results of a numerical study of influence of the Coulomb interaction on the rotational and translational motion of the C60 fullerene are presented.

Numerical simulation of interaction between multiphase flows and thin flexible structures

We develop a fluid–structure interaction numerical algorithm based on the immersed boundary (IB) method for simulating the interaction between air–water two-phase flows and thin flexible structures. In this algorithm, we propose a new method to avoid the unphysical fluxes across the thin structures, which effectively mitigates the issue of flow spurious penetration. In the proposed method, an explicit pressure boundary condition on the immersed boundary is applied. A new scheme for categorizing fluid, solid, and forcing nodes in the IB method is developed for avoiding extra pressure interpolation at the velocity projection step of the fractional-step method. The fluid motions are solved by a finite difference method. A coupled level-set and volume-of-fluid method is implemented to capture the free interface. A finite element method is utilized to solve the deformation of flexible plates. Two benchmark cases are tested and good agreement with the results in the literature is obtained.

Numerical Simulation of Interaction between Large-Scale Congestion and Vent during the Natural Gas Explosion in a Kitchen

The influence of large-scale congestion on a confined natural gas explosion in a typical Chinese kitchen was studied using the computational fluid dynamics technology. It was found that opening the explosion venting surface promotes the development of turbulence, flame propagation velocity, and multipeak overpressure in the explosion flow field. Large-scale congestion can significantly strengthen the influence of the explosion venting surface on the flow field; the congestion and the explosion venting surface have a synergistic effect on the explosion flow field. At the moment of gas explosion, the flow fields in each area of the kitchen exhibit different distribution characteristics. A flow field near small-scale congestion is more likely to produce greater turbulence, combustion rate, and flame speed. The obstruction effect of large-scale congestion perpendicular to the flame propagation direction is dominant. The indoor flame propagation speed and overpressure development speed increase and the peak combustion rate and indoor peak overpressure decrease with an increase in obstacle blockage. Increases in the large-scale volume congestion rate and volume blockage in the kitchen induce changes in the indoor flame propagation mode and increase the external explosion overpressure. This paper investigated the correlation behavior between large-scale congestion and vent surface in a typical Chinese civil kitchen during natural gas explosion process and provided important support for understanding the mechanism of congestion on gas explosion process and the distribution of explosion hazards in a kitchen.

Numerical investigation on nonlinear wave interaction with partially submerged subsea pipe-valve structures

The dynamic behaviours of subsea pipe-valve structures—the principal components of subsea equipment—are of critical concern for the control of the lowering through the splash zone during installation. Nonlinear interactions between waves and pipe-valve combinations are challenging the investigation of the wave forces acting on large-dimension structures. This paper proposes a numerical model to study the nonlinear hydrodynamic performance of partially submerged pipe-valve structures. A two-dimensional (2D) numerical water tank (NWT) was established to efficiently generate high-accuracy incident waves, and a semi-immersed horizontal cylinder was applied to the numerical simulations of wave-structure interaction (WSI) to study the mesh and time convergence. The numerical model was validated with a comparative analysis of the modelling results with experimental data, other numerical results, and theoretical results. Numerical simulations of the interaction between Stokes-II waves and subsea pipe-valve structures were performed, and the effects of the valve height ratio, valve length ratio, and valve spacing were investigated. The subsea pipe-valve structure is a kind of multi-scale structure, the wave forces exhibited stronger nonlinearity when acting on the partially submerged valves than on the completely submerged pipe. Changes in valve structure and distribution significantly increased the overall change in the wave forces acting on the valves. The stronger nonlinearity was primarily derived from phenomena such as wave reflection, wave blockage, and wave run-up. The numerical results provide references for the structure and strength designs and offshore installations of large subsea equipment like subsea manifolds.

Numerical simulation of interaction between vane wheel and propeller tip vortex

ABSTRACT The evolution of a propeller tip vortex and its effects on a vane wheel was investigated using a Reynolds Averaged Navier–Stokes simulation. A propeller and designed vane wheel were used to investigate the interaction between the tip vortex and the vane wheel, and the Q-criterion was used to evaluate the vortex of the propeller. The pressure fluctuation over the vane wheel was analysed. The simulation results show that the propeller tip vortex is shattered and dislocated. The influence of the vortex leads to a strong periodicity of the surface pressure of the vane wheel. The results within the frequency domain demonstrate that the amplitude of the probes located on the back of the vane wheel blade is larger than that of the probes located on the face. The numerical simulation shows that the pressure distribution on the propeller blade is very different from that on the vane blade.

Numerical Simulation of Interaction between Composite Breakwater and Seabed under Regular Wave Action by olaFlow Model

해안 · 항만구조물을 대표하는 í˜¼ì„±ë°©íŒŒì œì˜ 설계에서 파랑하중에 의한 사석마운드 및 í•´ì €ì§€ë°˜ì˜ 내부에서 과잉간극수압의 거동과 그에 따른 구조물의 파괴가 ë ¼ì˜ë˜ì–´ ì™”ê³ , 이를 ìˆ˜ì¹˜ì‹œë®¬ë ˆì´ì ˜ê¸°ë²•ìœ¼ë¡œ ê·œëª í•˜ë ¤ëŠ” 시도가 있어왔다. ìˆ˜ì¹˜ì‹œë®¬ë ˆì´ì ˜ì— 관한 대부분의 연구에서는 ì„ í˜• 및 ë¹„ì„ í˜•ì˜ 해석법이 ì ìš©ë˜ì—ˆì§€ë§Œ, 난류모델를 ê³ ë ¤í•œ ê°•ë¹„ì„ í˜•í•´ì„ë²•ì´ ì ìš©ëœ 사례는 거의 없었다. 본 연구에서는 VOF 법에 의한 쇄파현상과 LES 법에 의한 난류모델을 ê³ ë ¤í•˜ëŠ” ê³ ì •ë„ì˜ 혼상류해석법인 olaFlow 모델을 ì ìš©í•˜ì˜€ìœ¼ë©°, 규칙파-í•´ì €ì§€ë°˜ 및 규칙파-í˜¼ì„±ë°©íŒŒì œ-í•´ì €ì§€ë°˜ì˜ 상호작용해석에 관한 기존의 수치해석해 및 실험치와의 비교로부터 olaFlow 모델의 타당성을 ìž ì¦í•˜ì˜€ë‹¤. 이로부터 í˜¼ì„±ë°©íŒŒì œì˜ 케이슨과 사석마운드에서뿐만 아니라 í•´ì €ì§€ë°˜ì˜ 내부에서 규칙파랑하중에 의한 수평 파압, 과잉간극수압의 공간분포, í‰ê· ìœ ì†, í‰ê· ì™€ë„ì˜ 공간분포에 관한 특성 및 와도 크기의 í‰ê· ë¶„í¬ì™€ í‰ê· ë‚œë¥˜ 운동에너지와의 관계를 ê²€í† í•˜ì˜€ìœ¼ë©°, 나아가 í˜¼ì„±ë°©íŒŒì œì˜ ì•ˆì •ì„±ì„ ë ¼ì˜í•˜ì˜€ë‹¤. 핵심용어: olaFlow 모델, í˜¼ì„±ë°©íŒŒì œ, 사석마운드, í•´ì €ì§€ë°˜, 과잉간극수압, 와도, 난류운동에너지

Penetration of Double-Layer Targets with an Outer Ceramic Layer under the Action of an Impactor at an Angle

A three-dimensional numerical simulation of interaction between an impactor directed at an angle and a double-layer target with an outer ceramic layer is performed. It is shown that the presence of a ceramic layer normalizes the penetration process: the main deformation and displacement of the target elements occur so as if the action of the impactor is directed along a normal to the target surface. A quite intense rotation of the impactor remains at the final stages of interaction is observed. Experimental data and propositions on the transformation of the impact at an angle into an equivalent impact along the normal are used to develop an approximate analytical technique for calculating the limiting rate of penetrating the double-layer ceramic–metallic target under the action of the impactor at an angle.

Numerical Simulation of Interaction Between Red Blood Cell with Surrounding Fluid in Poiseuille Flow

Numerical Simulation of Interaction Between Red Blood Cell with Surrounding Fluid in Poiseuille Flow

Numerical Simulation of Interaction Between Soil and Pile Foundation of Bridge on Large-Scale Deposit Body

Bridge pile foundation on large-scale deposit body bears not only the vertical force transmitted from superstructure, but the lateral force transmitted from slope deformation, so the force situation is complex. The method of solving the internal force of piles which is simulated with solid elements is put forward in the paper. Taking Dahuaqiao bridge pile foundation as an example to carry out numerical simulation analysis. The distribution rules of axial force, shear force and bending moment of the pile in different position were analyzed. The results can provide the basis for the design and safety evaluation of bridge pile foundation.