Search Results (28)

Hydrodynamic journal bearings play a vital role in high-speed, heavy-load machinery. Their performance directly affects system efficiency and reliability. Supercritical carbon dioxide (S-CO₂), with its favorable thermophysical properties, is a promising lubricant. This study focused on a four-oil-cavity hydrodynamic journal bearing using S-CO₂ as the working fluid. A numerical model was established in ANSYS Workbench 2024 R1 using a fluid–structure interaction (FSI) method. The model was validated through comparison with literature data. Parametric studies were conducted by varying radial clearance, eccentricity, inlet diameter, and oil cavity size. Results showed that reducing the oil cavity wrap angle enhanced load capacity. Larger inlet diameters improved lubrication but could increase deformation. An appropriate combination of inlet diameter and eccentricity effectively reduced shell deformation. These findings offer design guidance for S-CO₂-lubricated bearings in high-speed applications. Full article

The dynamic behavior of pipelines subjected to additional masses is crucial for optimizing the design and reliability of engineering systems, particularly in offshore and industrial applications. This study investigates the effect of slenderness on the dynamic response of a pipe with one or more additional masses placed at different positions along its length, considering the symmetry of the system in mass distribution. The aim is to analyze how mass placement influences vibration characteristics under fluid–structure interaction (FSI) conditions. The pipe is modeled as a Rayleigh beam, and the governing equations of motion are derived using Hamilton’s principle while preserving the inherent symmetry of the system. A non-dimensionalized approach is employed to ensure broad applicability across different geometric and material configurations. The vibration frequencies are obtained using the Galerkin method (GM) and validated via a two-way FSI technique, integrating computational fluid dynamics (CFDs) and structural mechanics using ANSYS 2022 software. The results demonstrate the relationship between the concentrated mass ratio and vibration frequency for the first three modes, highlighting the influence of slenderness ratio on system stability. These findings provide valuable insights for the engineering design of pipeline systems subjected to dynamic loading. Full article

This research investigates the seismic behavior of rigid and flexible cylindrical steel tanks, focusing on tanks with an open top and fully anchored at the base. The primary objective is to evaluate the hydrodynamic pressures exerted by the fluid on the tank walls during seismic excitation. Three widely recognized design approaches—New Zealand NZSEE recommendations, European code UNI EN 1998-4:2006 (CEN, 2006), and American Water Works Association AWWA D100-05 standard (ANSI/AWWA, 2005)—were implemented and compared with high-definition finite element models and then validated against the experimental results. Nonlinear fluid–structure interaction (FSI) was modeled using an Arbitrary Lagrangian–Eulerian (ALE) formulation with the Navier–Stokes equations governing the fluid motion and material and geometric nonlinearities considered in the tank walls. Parametric analyses were conducted to investigate the impact of tank geometry, specifically height-to-radius and radius-to-thickness ratios, on seismic response, identifying a transition between rigid and flexible behavior. The study also examined the influence of seismic input using a set of ten displacement spectrum-compatible ground motions. The findings contribute to a better understanding of the seismic resilience of cylindrical steel tanks, offering valuable insights for improving design standards and safety in earthquake-prone regions where these systems may abound. Full article

Xinjiang, as a major agricultural region, offers extensive application potential for hose pumps, given their excellent performance as fertilization devices. Analyzing the pulsation characteristics of hose pumps during operation is valuable for reducing noise and extending pump service life. To investigate the pulsation characteristics and unsteady flow of hose pumps with different roller numbers, this study adopts a bidirectional fluid-structure interaction (FSI) method and utilizes ANSYS 19.0 commercial finite element software to analyze the outlet and inlet pressure pulsations, outlet flow velocity pulsations, and the distribution of the flow field at the intermediate plane for both two-roller and three-roller pumps transporting high and low Reynolds number fluids under the same working conditions. It was observed that the three-roller pump exhibited higher outlet pressure compared with the inlet and that the pulsation intensity was lower in the three-roller pump than in the two-roller pump under the same conditions, with an analysis provided on the reasons for this phenomenon. This study offers theoretical support for the selection and further optimization of hose pump designs. To further reduce the negative effects of pulsations, it is recommended to increase the number of rollers in the design while also considering shape optimization of the pump casing or using feedback control systems to adjust and reduce pulsation intensity. Full article

This study examines the static performances of a graphene platelet (GPL)-reinforced ethylene tetrafluoroethylene (ETFE) composite membrane under wind loadings. The wind pressure distribution on a periodic tensile membrane unit was analyzed by using CFD simulations, which considered various wind velocities and directions. A one-way fluid–structure interaction (FSI) analysis incorporating geometric nonlinearity was performed in ANSYS to evaluate the static performances of the composite membrane. The novelty of this research lies in the integration of graphene platelets (GPLs) into ETFE membranes to enhance their static performance under wind loading and the combination of micromechanical modelling for obtaining material properties of the composites and finite element simulation for examining structural behaviors, which is not commonly explored in the existing literature. The elastic properties required for the structural analysis were determined using effective medium theory (EMT), while Poisson’s ratio and mass density were evaluated using rule of mixtures. Parametric studies were carried out to explore the effects of a number of influencing factors, including pre-strain, attributes of wind, and GPL reinforcement. It is demonstrated that higher initial strain effectively reduced deformation under wind loads at the cost of increased stress level. The deformation and stress significantly increased with the increase in wind velocity. The deflection and stress level vary with the wind direction, and the maximum values were observed when the wind comes at 15° and 45°, respectively. Introducing GPLs with a larger surface area into membrane material has proven to be an effective way to control membrane deformation, though it also results in a higher stress level, indicating a trade-off between deformation management and stress management. Full article

Background and Objectives: Hypertension increases the risk of developing atherosclerosis and arterial stiffness, with secondarily enhanced wall stress pressure that damages the artery wall. The coexistence of atherosclerosis and hypertension leads to artery stenosis and microvascular angiopathies, during which the intravascular mechanical hemolysis of red blood cells (RBCs) occurs, leading to increased platelet activation, dysfunction of the endothelium and smooth muscle cells due to a decrease in nitric oxide, and the direct harmful effects of hemoglobin and iron released from the red blood cells. This study analyzed the impact of hypertension and physical exercise on the risk of hemolysis in the left coronary artery. Methods: To analyze many different cases and consider the decrease in flow through narrowed arteries, a flow model was adopted that considered hydraulic resistance in the distal section, which depended on the conditions of hypertension and exercise. The commercial ANSYS Fluent 2023R2 software supplemented with user-defined functions was used for the simulation. CFD simulations were performed and compared with the FSI simulation results. Results: The differences obtained between the FSI and CFD simulations were negligible, which allowed the continuation of analyses based only on CFD simulations. The drops in pressure and the risk of hemolysis increased dramatically with increased flow associated with increased exercise. A relationship was observed between the increase in blood pressure and hypertension, but in this case, the increase in blood pressure dropped, and the risk of hemolysis was not so substantial. However, by far, the case of increased physical activity with hypertension had the highest risk of hemolysis, which is associated with an increased risk of clot formation that can block distal arteries and lead to myocardial hypoxia. Conclusions: The influence of hypertension and increased physical exercise on the increased risk of hemolysis has been demonstrated. Full article

The hydrofoil plays a crucial role in tidal current energy (TCE) devices, such as horizontal-axis turbines (HATs), vertical-axis turbines (VATs), and oscillating hydrofoils. This study delves into the numerical investigation of passive chordwise and spanwise deformations and the hydrodynamic performance of a deformable hydrofoil. Three-dimensional (3D) coupled fluid–structure interaction (FSI) simulations were conducted using the ANSYS Workbench platform, integrating computational fluid dynamics (CFD) and finite element analysis (FEA). The simulation involved a deformable hydrofoil undergoing pitching motion with varying elastic moduli. The study scrutinizes the impact of elastic modulus on hydrofoil deformation, pressure distribution, flow structure, and hydrodynamic performance. Coefficients of lift, drag, torque, as well as their hysteresis areas and intensities, were defined to assess the hydrodynamic performance. The analysis of the correlation between pressure distribution and deformation elucidates the FSI mechanism. Additionally, the study investigated the 3D effects based on the flow structure around the hydrofoil. Discrepancies in pressure distribution along the spanwise direction result from these 3D effects. Consequently, different chordwise deformations of cross-sections along the spanwise direction were observed, contributing to spanwise deformation. The pressure difference between upper and lower surfaces diminished with increasing deformation. Peak values and fluctuations of lift, drag, and torque decreased. This study provides insights for selecting an appropriate elastic modulus for hydrofoils used in TCE devices. Full article

A structure located in seismic regions must have a resistance capacity based on current seismic design codes and maintain this capacity for its design life. However, the responses of structures to several major earthquakes worldwide over the past decade have demonstrated the inadequacy of current seismic design codes. Thus, there is a need for an accurate method for assessing the strength of structures under seismic loads. Accordingly, this study aimed to numerically review the structural performance of a typical firefighting water tank equipped with an anti-wave plate under seismic loads. Quasi-static and transient structural analysis methods were developed to determine the structural strength of the water tank. In addition, a one-way fluid–structure interaction (FSI) method was developed to analyse the effect of the anti-wave plate on the liquid-sloshing motion in and the structural strength of the water tank. Moreover, convergence tests were performed to aid the development of mesh models and grid models for finite element method and finite volume method analyses, respectively. Subsequently, the structural responses of the water tank were determined via quasi-static, transient, and one-way FSI analyses. Finally, the effectiveness of the anti-wave plate for mitigating the sloshing pressure in the water tank and the structural responses according to the pressure change were analyzed. The commercial software ANSYS Workbench (ver. 2020R2) was used. Full article

The sudden increase in the operating pressure of nuclear power plants (NPPs) is due to the water hammer phenomenon, which tends to produce a whipping effect that causes serious damage to the pipes and their surroundings. The mechanical response of these pipelines under the influence of such fast fluid transients can be estimated using the fluid–structure interaction (FSI) method. The computational time and expense are predominantly dependent on the number of finite elements developed in the model. Hence, an effective modeling technique with limited and efficient nodes and elements is desired to obtain the closest possible results. A coupled 1D/3D finite element modeling approach using the FSI method is proposed to determine the influence of fast transients on the mechanical pipe whipping behavior of gas pipelines in NPPs. The geometric coupled modeling approach utilizes the presence of both the 3D solid elements and the 1D beam elements sharing a local conjunction. The computational model is modelled for a pipe-to-wall impact test scenario taken from the previously conducted French Commissariat a l’Energie Atomique (CEA) pipe whip experiments. The results of displacement, stresses, and impact velocity at the 3D section featuring the elbow are compared for the change in the 3D solid length varied at the juncture of the elbow. The computed results from the Ansys FSI coupling method using the Fluent and Transient Structural modules provides fair validation with the previously conducted experimental results and correlates with the CEA pipe whip tests on pipe-to-wall impact models. Thus, the 1D/3D coupled modeling approach, which minimizes the area of the solid region by constricting it to the impact area with appropriate contact modeling at the junctures, can be considered in the future for decreasing the computational time and the creation of finite elements. Full article

This study proposes a novel reduced-order model (ROM), based on the Volterra series, for the aerodynamic force of the bridge deck section. Moreover, the ROM of the aerodynamic force of the streamlined box girder section of the Great Belt East Bridge (GBEB) is identified with computational fluid dynamic (CFD) simulations. Furthermore, an analysis method combining ROM aerodynamic force and Newmark-β integration is established to simulate the aeroelastic responses of the bridge deck section. Finally, the wind-induced vibration responses of the GBEB section are calculated near the flutter critical wind speed based on the Volterra series-based aeroelastic analysis and the fluid–structure interaction (FSI) numerical simulations in ANSYS Fluent, respectively. Moreover, to verify the applicability of the proposed method, the aeroelastic responses of the main deck section with the crash barriers of Lingdingyang Bridge (LDYB) are also simulated via the Volterra model and Newmark-β integration near the flutter critical wind speed. The results show that the first-order truncated Volterra model established in this study can accurately capture the aerodynamic response of the main girder, and the results are in good agreement with those of the CFD numerical simulation under forced vibration. Furthermore, the proposed method combined with ROM aerodynamic force and Newmark-β integration can effectively calculate the FSI of the bridge girder. The numerical results of the flutter critical wind speed and flutter frequency of GBEB and LDYB are consistent with the numerical results by the FSI method based on ANSYS Fluent and the existing numerical and experimental results, respectively. Full article

Dam reliability analysis is performed to determine the structural integrity of dams and, hence, to prevent dam failure. The Chenderoh Dam structure is divided into five parts: the left bank, right bank, spillway, intake section, and bottom outlet, with each element performing standalone functions to maintain the overall Dam’s continuous operation. This study presents a numerical reliability analysis of water dam reservoir banks using fluid–structure interaction (FSI) simulation of the bottom outlet structures operated at different discharge conditions. Three-dimensional computer-aided drawings were used to view the overall Chenderoh Dam. Next, a two-way fluid–structure interaction (FSI) model was developed to explore the influence of fluid flow and structural deformation on dam systems. The FSI modeling consists of Ansys Fluent and Ansys Structural modules to consider the boundary conditions separately. The reliability and performance of the reservoir bottom outlet structure was effectively simulated and recognised using FSI. The maximum stress on the bottom outlet section is 18.4 MPa, which is lower than the yield stress of mild steel of 370 MPa. Therefore, there will be no structural failure being observed on the bottom outlet section when the butterfly valve is fully closed. With a few exceptions, the FSI models projected that bottom outlet structures would be able to run under specified conditions without structural collapse or requiring interventions due to having lower stress than the material’s yield strength. Full article

Safety and reliable operation is one of the most important research areas for centrifugal pump systems, due to the interaction of complex flow, large structural load, and vibration caused by the operation of the impeller. To analyze the internal flow and impeller deformation of the centrifugal pump, the single-stage single-suction centrifugal pump titled IS100-80-160 was selected as the research object. Under the principle of single variable, the turbulent flow and structural response of three impellers designed by different parameters were calculated by CFX and ANSYS Workbench. A numerical simulation of steady flow at different flow rates of the centrifugal pump was carried out, and its hydraulic performance is consistent with the corresponding experimental results. By comparing the deformation of the impeller rotor system, it was found that the closed impeller has the worst stability with the best hydraulic performance; the impeller with split blades has the worst stability with the best hydraulic performance. This study could enhance the understanding of impeller FSI on centrifugal pump stability and provide a reference for improving the operational stability of centrifugal pumps. Full article

This research paper focuses on a novel coupling of the aerodynamic and structural behaviour of a double-element composite front wing of a Formula One (F1) vehicle, which was simulated and studied for the first time here. To achieve this goal, a modified two-way coupling method was employed in the context of high performance computing (HPC) to simulate a steady-state fluid-structure interaction (FSI) configuration using the ANSYS software package. The front wing plays a key role in generating aerodynamic forces and controlling the fresh airflow to maximise the aerodynamic performance of an F1 car. Therefore, the composite front wing becomes deflected under aerodynamic loading conditions due to its elastic behaviour which can lead to changes in the flow field and the aerodynamic performance of the wing. To reduce the uncertainty of the simulations, a grid sensitivity study and the assessment of different engineering turbulence models were carried out. The practical contribution of our investigations is the quantification of the coupled effect of the aerodynamic and structural performance of the wing and an understanding of the influence of ride heights on the ground effect. It was found that the obtained numerical surface pressure distributions, the aerodynamic forces, and the wake profiles show an accurate agreement with experimental data taken from the literature. Full article

Floating offshore structures (FOS) must be designed to be stable, to float, and to be able to support other structures for which they were designed. These FOS are needed for different transfer operations in oil terminals. However, water waves affect the motion response of floating buoys. Under normal sea states, the free-floating buoy presents stable periodic responses. However, when moored, they are kept in position. Mooring configurations used to moor buoys in single point mooring (SPM) terminals could require systems such as Catenary Anchor Leg Moorings (CALM) and Single Anchor Leg Moorings (SALM). The CALM buoys are one of the most commonly-utilised type of offshore loading terminal. Due to the wider application of CALM buoy systems, it is necessary to investigate the fluid structure interaction (FSI) and vortex effect on the buoy. In this study, a numerical investigation is presented on a CALM buoy model conducted using Computational Fluid Dynamics (CFD) in ANSYS Fluent version R2 2020. Some hydrodynamic definitions and governing equations were presented to introduce the model. The results presented visualize and evaluate specific motion characteristics of the CALM buoy with emphasis on the vortex effect. The results of the CFD study present a better understanding of the hydrodynamic parameters, reaction characteristics and fluid-structure interaction under random waves. Full article

Currently available small diameter vascular grafts (<6 mm) present several long-term limitations, which has prevented their full clinical implementation. Computational modeling and simulation emerge as tools to study and optimize the rational design of small diameter tissue engineered vascular grafts (TEVG). This study aims to model the correlation between mechanical-hemodynamic-biochemical variables on protein adsorption over TEVG and their regenerative potential. To understand mechanical-hemodynamic variables, two-way Fluid-Structure Interaction (FSI) computational models of novel TEVGs were developed in ANSYS Fluent 2019R3^® and ANSYS Transient Structural^® software. Experimental pulsatile pressure was included as an UDF into the models. TEVG mechanical properties were obtained from tensile strength tests, under the ISO7198:2016, for novel TEVGs. Subsequently, a kinetic model, linked to previously obtained velocity profiles, of the protein-surface interaction between albumin and fibrinogen, and the intima layer of the TEVGs, was implemented in COMSOL Multiphysics 5.3^®. TEVG wall properties appear critical to understand flow and protein adsorption under hemodynamic stimuli. In addition, the kinetic model under flow conditions revealed that size and concentration are the main parameters to trigger protein adsorption on TEVGs. The computational models provide a robust platform to study multiparametrically the performance of TEVGs in terms of protein adsorption and their regenerative potential. Full article