Numerical Analysis Of Interaction Research Articles

Numerical analysis of interaction between flow characteristics and dynamic response of interlocked concrete block mattress during sinking process

Revetment can provide effective protection against wave overtopping and fluvial erosion along coastlines, estuaries, and rivers. The cost-effectiveness and rapid implementation make Interlocked Concrete Block Mattress (ICB mat) a viable alternative to unit armors. However, the intense hydrodynamic conditions may compromise the structural integrity of ICB mat during sinking construction, posing significant threats to both personnel and engineering safety. This study aimed to investigate the flow characteristics around the flexible mattress and its dynamic response. Recently, the fluid-structure interaction (FSI) method has been extended to multi-physics analysis in engineering applications due to its superior performance. A two-way coupling was employed to simulate the conceptualized cases of sinking process of ICB mat using the k-ω SST turbulence model, the Arbitrary Lagrangian-Eulerian algorithm, and the partitioned method in this study. The results indicated that the upstream surface velocity of the mattress increased exponentially with the growing water depth; meanwhile, the maximum velocity near the head beam was 23.8–31.2% larger than the average velocity. Additionally, the stress distribution on the mattress manifested transverse stripes influenced by the layout of interlocked blocks, with the highest stress primarily observed in the vicinity of the rotating plate and head beam. Furthermore, an estimation formula was proposed for the dynamic response of ICB mat considering the hydrodynamic conditions as well as structural properties. The current study can provide theoretical guidance for the structural design of ICB mat and engineering risk assessment during sinking construction.

Numerical analysis of interaction between sea ice and propeller based on coupled DEM-FEM model

When a ship navigates through ice-covered seas, the interaction between sea ice and propellers damages the propeller blades. A coupled discrete element method (DEM)-finite element method (FEM) model was developed to investigate the interaction between an ice block and a propeller. The ice block and ice-class propeller were simulated using the sphere-based DEM and hexahedral solid elements of the FEM, respectively. According to the mechanical mechanism of the ice-blade interaction, the compressive strength of sea ice is the most important parameter for the simulation. The bonding strength between the element was determined by the element size and compressive strength of the sea ice material through uniaxial tests. Then, the ice-propeller interaction was simulated using the proposed DEM-FEM model. The convergence of the proposed numerical model was verified. For simulating the ice-propeller milling process, four parameters, i.e., carriage speed, cut depth, rotational speed, and ice strength, were investigated to analyze the ice load and dynamic response of the propeller. Finally, considering the randomness of the ice-propeller interaction with the real condition, a numerical simulation of ice-propeller interaction during backward sailing of the ship was established, and the random characteristics of the ice load on the blades were analyzed.

Numerical analysis of interaction between turbulent structures and transient sheet/cloud cavitation

This paper through the in-house code numerically examines the cavitation–vortex–turbulence interaction mechanism. The high grid resolution can obtain a more detailed flow field structure, which is helpful to reveal the relationship between cavitation occurrence and development and local turbulent flow field. Results are presented for a three-dimensional NACA66 hydrofoil fixed at an 8° angle of attack under a moderate Reynolds number of 1 × 106 and sheet/cloud cavitating conditions. Numerical simulations are performed via the boundary data immersion method coupled with the artificial compressibility method through a Fortran-based code. The results show that the numerical predictions are capable of capturing the unsteady cavitation characteristics, in accordance with the quantitative features observed in high-speed cavitation tunnel experiments. The evolution of the transient cavitating flow can be divided into three stages: growth of the attached sheet cavity, development of a re-entrant jet, and cloud shedding downstream. The Liutex method is applied to capture the vortex structure. Further analysis of the process of enstrophy transport reveals that cavitation promotes vortex production and increases the enstrophy as the cavity becomes more unstable. Moreover, the structure of the vortex gradually evolves from a vortex tube to a U-type vortex, Ω-type vortex, and streamwise vortex. Finally, the interaction between cavitation and turbulence is expounded using the turbulent energy transport equation, which demonstrates that cavitation promotes the production, diffusion, and dissipation of turbulent kinetic energy, while the viscous transport term only acts during the process of cloud cavity shedding.

Numerical analysis of interaction between a model tunnel lining and non-cohesive soil

The paper presents an analysis and assessment of an interaction between a model tunnel lining and surrounding non-cohesive soil. The analysis was conducted with numerical simulations using the author’s program based on an algorithm of the discrete element method. Previously calibrated numerical model was used in the calculations. Calibration was based on comparison of the construction deformations observed in the laboratory tests and during the simulation. Numerous simulations, performed in the calibrated numerical model, included calculations for a flexible and rigid construction of the lining. The tunnel construction loads, stress distribution in the surrounding soil, and soil particles’ displacements were investigated. Analyses were conducted in two variants — when only soil weight is acting on the tunnel construction and when the external load transmitted from the surface is present. Also two variants of the backfill height were investigated — they were equal to one and two diameters of the tunnel. The values of tunnel loads, which were numerically calculated, were compared with the corresponding values, calculated by the Hewett’s method. It is shown that distribution of tunnel loads and stresses in the surrounding soil is strongly linked with the tunnel construction stiffness, thus it can be significantly different from standard load situations for such constructions. Keywords: civil engineering, discrete element method, tunnel lining

Numerical analysis of interaction between seabed and mono-pile subjected to dynamic wave loadings considering the pile rocking effect

Pile rocking is the motion of a mono-pile foundation as a result of cyclic loads caused by wind and wave, and the effect of upper structures such as offshore wind turbines. The rocking effect further complicates the interaction between a mono-pile and the seabed and results in instability of offshore structures. In this research, a three-dimensional integrated numerical model, combining the effect of wave loads with the seabed and mono-pile, is adopted to investigate wave-structure-seabed interaction (WSSI) considering the pile rocking effect. The present model is validated by available laboratory experiment data and analytical results. In addition, a detailed comparison with a non-rocking single pile is conducted to examine the effect of pile rocking on soil response more clearly. Finally, the momentary liquefaction depth is investigated and a parametric study on pore pressure response has been carried out. Results indicate that local pressure enlargement occurs near the mudline and the rate of pore pressure decrease in depth is slowed down due to pile rocking, leading to a relatively high pore pressure in the upper soil range. Furthermore, the pile rocking effect has a significant influence on the liquefaction distribution and enlarges the liquefaction zone in the vicinity of mono-pile foundation.

Numerical Analysis of Interactions and Heat Transfer between Asymmetric Hairpin Vortices in the Wakes behind a Staggered Array of Asymmetric Hills

Numerical Analysis of Interactions and Heat Transfer between Asymmetric Hairpin Vortices in the Wakes behind a Staggered Array of Asymmetric Hills

Three-dimensional Numerical Analysis of Interaction between Arc and Pool by Considering the Behavior of the Metal Vapor in Stationary Activating Tungsten Inert Gas Welding

Three-dimensional Numerical Analysis of Interaction between Arc and Pool by Considering the Behavior of the Metal Vapor in Stationary Activating Tungsten Inert Gas Welding

Numerical analysis of interaction between non-gray radiation and forced convection flow over a recess using the full-spectrum k-distribution method

In the present work, the interaction between non-gray radiation and forced convection in a laminar radiating gas flow over a recess including two backward and forward facing steps in a duct is investigated numerically. Distributions of absorption coefficients across the spectrum (50 cm−1 < η < 20,000 cm−1) are obtained from the HITRAN2008 database. The full-spectrum k-distribution method is used to account for non-gray radiation properties, while the gray radiation calculations are carried out using the Planck mean absorption coefficient. To find the divergence of radiative heat flux distribution, the radiative transfer equation is solved by the discrete ordinates method. The effects of radiation–conduction parameter, wall emissivity, scattering coefficient and recess length on heat transfer behaviors of the convection–radiation system are investigated for both gray and non-gray mediums. In addition, the results of gray medium are compared with non-gray results in order to judge if the differences between these two approaches are significant enough to justify the usage of non-gray models. Results show that for air mixture with 10 % CO2 and 20 % H2O, use of gray model for the radiative properties may cause significant errors and should be avoided.

Application of full-spectrum k-distribution method to combined non-gray radiation and forced convection flow in a duct with an expansion

This paper presents a numerical analysis of interaction between non-gray radiation and laminar forced convection flow in a duct with an expansion. Distributions of absorption coefficients across the spectrum (50 cm −1 < η < 20000 cm −1) are obtained from the HITRAN2008 database. The full spectrum k-distribution method (FSK) is used to deal with the non-gray part of the problem, while the gray radiation calculations are carried out using the Planck mean absorption coefficient. In addition, the results of non-gray medium are compared with the gray results in order to judge if the differences between these two approaches are significant enough to justify the usage of non-gray models. Results show that for air mixtures with different mole fractions of CO2 and H2O, use of gray model for the radiative properties may leads to considerable errors and should be eschewed.

Numerical analysis of interaction between solute atom and extended dislocation using force multipoles

The interaction between a solute atom and an extended dislocation was investigated using a continuum approximation method with force multipoles. The dislocation core structure of extended dislocation was modeled with the Peierls-Nabarro model discretized with a number of infinitesimal Volterra dislocations. The interaction energy and force between a nickel solute atom and perfect and extended dislocation in copper were successfully calculated using the force multipoles. The results clearly show that the core structure of extended dislocation weakens the interaction with solute atoms. The interaction energy and force for extended dislocations are almost the half of those for perfect dislocations.

Numerical Analysis of Interaction of Single Pile and Soil Based on ADINA

The interaction between pile and soil can not be ignored in the seismic analysis of long-span bridges. Earthquake action in the form of lateral load apply on the pile through the soil, the analysis of pile under lateral load is very important in aseismatic analysis of bridge. Analysis of the horizontal load pile-soil interaction by using finite element analysis software ADINA, establishing the three-dimensional contact model of pile-soil interaction and the analysis model by using p-y curve model of soil-pile interaction respectively. Comparing the displacement of the top of pile with the actual measurements to verify the numerical method is right. It shows that the feasibility of using ADINA for pile-soil interaction analysis.

Numerical Analysis of Interaction Between Single-Pulse Laser-Induced Plasma and Bow Shock in a Supersonic Flow

The interaction of laser-induced plasma and bow shock over a blunt body is investigated numerically in an M∞ = 6.5 supersonic flow. A ray-tracing method is used for simulating the process of laser focusing. The gas located at the focused zone is ionized and broken down and transformed into plasma. In a supersonic flow the plasma moves downstream and begins to interact with the bow shock when it approaches the surface of the blunt body. The parameters of flowfield and blunt body surface are changed due to the interaction. By analyzing phenomena occurring in the complex unsteady flowfield during the interaction in detail, we can better understand the change of pressure on the blunt body surface and the mechanism of drag reduction by laser energy deposition. The results show that the bow shock is changed into an oblique shock due to the interaction of the laser-induced low-density zone with the bow shock, so the wave drag of the blunt body is reduced.

Numerical Analysis of Interaction Between Inertial and Thermosolutal Buoyancy Forces on Convective Heat Transfer in a Lid-Driven Cavity

In this paper, results on double diffusive mixed convection in a lid-driven cavity are discussed in detail with a focus on the effect of interaction between fluid inertial force and thermosolutal buoyancy forces on convective heat and mass transfer. The governing equations for the mathematical model of the problem consist of vorticity transport equation, velocity Poisson equations, energy equation and solutal concentration equation. Numerical solution for the field variables are obtained by solving the governing equations using Galerkin’s weighted residual finite element method. The interaction effects on convective heat and mass transfer are analyzed by simultaneously varying the characteristic parameters, 0.1&lt;Ri&lt;5, 100&lt;Re&lt;1000, and buoyancy ratio (N), −10&lt;N&lt;10. In the presence of strong thermosolutal buoyancy forces, the increase in fluid inertial force does not make significant change in convective heat and mass transfer when the thermal buoyancy force is smaller than the fluid inertial force. The fluid inertial force enhances the heat and mass transfer only when the thermal buoyancy force is either of the same magnitude or greater than that of the fluid inertial force. The presence of aiding solutal buoyancy force enhances convective heat transfer only when Ri becomes greater than unity but at higher buoyancy ratios, the rate of increase in heat transfer decreases for Re=400 and increases for Re=800. No significant change in heat transfer is observed due to aiding solutal buoyancy force for Ri≤1 irrespective of the Reynolds number.

Numerical Analysis of Interaction Between Earth and Large Foundations Regarding Size Effect

Numerical Analysis of Interaction Between Earth and Large Foundations Regarding Size Effect

515 境界要素法を用いた浮体と気泡との相互干渉に関する数値計算(OS-7 熱流体の非線形力学とその数値シミュレーション(3))

515 境界要素法を用いた浮体と気泡との相互干渉に関する数値計算(OS-7 熱流体の非線形力学とその数値シミュレーション(3))

Numerical analysis of interaction and coalescence of numerous microcracks

The deformation and failure behaviors of brittle or quasi-brittle solids are closely related to interaction and propagation of stochastically distributed microcracks. The influence of microcrack interaction and evolution on the mechanical properties of materials presents a problem of considerable interest, which has been extensively argued but has not been resolved as yet. In the present paper, a novel numerical method is used to calculate the effective elastic moduli and the tensile strength, and to simulate the failure process of brittle specimens containing numerous microcracks. The influences of some crack distribution parameters reflecting the non-uniform spatial concentration, size and orientation distributions are examined. The effective elastic moduli and the tensile strength of brittle materials exhibit different dependences on microcrack interaction. For example, two microcrack distributions that lead to the identical effective elastic moduli may cause a pronounced difference in the tensile strengths and failure behaviors of materials. By introducing two criteria for microcrack growth and coalescence in terms of Griffith’s energy release rate, the above numerical method is extended to simulate the coalescence process of microcracks that results in a fatal crack and the final rupture of a specimen.

電離層プラズマ―高電圧ソーラーパネル間相互作用の数値解析

電離層プラズマ―高電圧ソーラーパネル間相互作用の数値解析

Numerical Analysis of Interaction between Single Bubble and Shock Wave.

The Arbitrary Lagrangian-Eulerian (ALE) method is used to predict the collapse and rebound of a bubble in a compressible viscous liquid by taking account of the flow inside the bubble. Computations are performed for the interaction between a gas bubble and an incident shock wave. It is shown that when the incident shock wave is strong, the deformation of the bubble surface occurs in the early stage of collapse. When the pressure behind the incident shock wave, p0, is 101.3 MPa, an internal shock wave arises, thus considerably increasing the local temperature inside the bubble. 0n the other hand, when p0 is less than about 1.013 MPa, the liquid pressure increases almost uniformly after the incident shock wave passes through the bubble, and therefore, the state of the gas inside the bubble can be regarded as nearly uniform. It is also shown that although the velocity of the microjet becomes faster with the increase of p0, the increasing rate of jetvelocity is suppressed when the jetvelocity approaches to the velocity of sound in the liquid.

Prospects for numerical analysis of interaction between fluid flow and structural vibration

Prospects for numerical analysis of interaction between fluid flow and structural vibration

Prospects for numerical analysis of interaction between fluid flow and structural vibration

Publisher Summary Prospects for numerical analysis of interaction between fluid flow and structural vibration research needs in the emerging field of computational wind engineering (CWE) are driven in large part by the wind engineering requirements of the structural engineering community. This includes efforts to accurately simulate, aerodynamically tailor and/or control the structural motions that result from the wind. The prospect of practically applying the results of numerical simulations of fluid flows about bluff body analogues of flexible, vibrating civil structures was examined and discussed during in a workshop held specifically for this purpose during the CWE92, Symposium, University of Tokyo, August, 1992. Progresses of CWE were demonstrated by individual workshop participants who summarized their views on the future prospect. Three themes or key issues came to the forefront during panel discussions after workshop presentations: (1) CWE as a possible tool in structural design practice, (2) accuracy and reliability of the numerical solutions, and (3) the role of experiment and wind tunnel testing in CWE.