Search results
1 – 10 of 96The simulation of the fluid–solid interaction (FSI) problem is important for both academic studies and engineering applications. However, the numerical approach for simulating the…
Abstract
Purpose
The simulation of the fluid–solid interaction (FSI) problem is important for both academic studies and engineering applications. However, the numerical approach for simulating the FSI problems is a great challenge owing to the large discrepancy of material properties and inconsistent description of grid motion between the fluid and solid domains. The difficulties will be further increased if there are multiple materials in the fluid region. In these complicated applications, interface reconstruction, multi-material advection and FSI must be all taken into account. This paper aims to present an effective integrated work of multi-material arbitrary Lagrangian Eulerian (MMALE) method, finite element (FE) method and the continuum analogy method to simulate the complex FSI problems involving multi-material flow. The coupled method is used to simulate the three-dimensional CONT test and the blast-plate interaction. The numerical results show good agreement with the benchmark and the experiment data, which indicates that the presented method is effective for solving the complicated FSI problems.
Design/methodology/approach
MMALE and FE methods are used to simulate fluid and solid regions, respectively. The interfacial nodes of fluid and solid are required to be coincident in the whole simulation so the interacted force can be easily and accurately calculated. To this end, the continuum analogy method is used in the rezoning phase.
Findings
The coupled method is used to simulate the three-dimensional CONT test and the blast-plate interaction. The numerical results show good agreement with the benchmark and the experiment data, which indicates that the presented method is effective for solving the complicated FSI problems.
Originality/value
To the best of the authors’ knowledge, this is the first time that the ALE method, moment of fluid interface reconstruction method, continuum analogy method and the FE method are combined to solve complicated practical problems.
Details
Keywords
Liming Zhai, Yongyao Luo, Xin Liu, Funan Chen, Yexiang Xiao and Zhengwei Wang
The purpose of this paper is to analyze lubrication characteristics of a tilting pad thrust bearing considering the effect of the thermal elastic deformation of the pad and collar.
Abstract
Purpose
The purpose of this paper is to analyze lubrication characteristics of a tilting pad thrust bearing considering the effect of the thermal elastic deformation of the pad and collar.
Design/methodology/approach
This study used the fluid–solid interaction (FSI) technique to investigate the lubrication characteristics of a tilting pad thrust bearing for several typical operating conditions. The influences of the rotational speed, the thrust load and the oil supply temperature on the lubrication characteristics were analyzed.
Findings
The three-dimensional (3D) film model clearly shows that there is no pressure gradient but large temperature gradients across the film thickness. The wall heat transfer coefficients on the pad surfaces distribute in a very complex way and change within a large range. The rotational speed, the thrust load and the oil supply temperature have great but different influences on the lubrication characteristics.
Originality/value
This paper has preliminarily revealed the lubrication mechanism of the tilting-pad thrust bearings. The 3D FSI method is suggested to evaluate the thermal-elastic-hydrodynamic deformations of thrust bearings instead of the conventional method which iteratively solves the Reynolds equation, the energy equation, the heat conduction equation and the elastic equilibrium equation. Using FSI method, the heat transfer coefficients on the pad surfaces can be evaluated better.
Details
Keywords
Jonathan Núñez Aedo, Marcela A. Cruchaga and Mario A. Storti
This paper aims to report the study of a fluid buoy system that includes wave effects, with particular emphasis on validating the numerical results with experimental data.
Abstract
Purpose
This paper aims to report the study of a fluid buoy system that includes wave effects, with particular emphasis on validating the numerical results with experimental data.
Design/methodology/approach
A fluid–solid coupled algorithm is proposed to describe the motion of a rigid buoy under the effects of waves. The Navier–Stokes equations are solved with the open-source finite volume package Code Saturne, in which a free-surface capture technique and equations of motion for the solid are implemented. An ad hoc experiment on a laboratory scale is built. A buoy is placed into a tank partially filled with water; the tank is mounted into a shake table and subjected to controlled motion that promotes waves. The experiment allows for recording the evolution of the free surface at the control points using the ultrasonic sensors and the movement of the buoy by tracking the markers by postprocessing the recorded videos. The numerical results are validated by comparison with the experimental data.
Findings
The implemented free-surface technique, developed within the framework of the finite-volume method, is validated. The best-obtained agreement is for small amplitudes compatible with the waves evolving under deep-water conditions. Second, the algorithm proposed to describe rigid-body motion, including wave analysis, is validated. The numerical body motion and wave pattern satisfactorily matched the experimental data. The complete 3D proposed model can realistically describe buoy motions under the effects of stationary waves.
Originality/value
The novel aspects of this study encompass the implementation of a fluid–structure interaction strategy to describe rigid-body motion, including wave effects in a finite-volume context, and the reported free-surface and buoy position measurements from experiments. To the best of the authors’ knowledge, the numerical strategy, the validation of the computed results and the experimental data are all original contributions of this work.
Details
Keywords
Liming Zhai, Zhengwei Wang, Yongyao Luo and Zhongjie Li
The purpose of this paper is to analyze lubrication characteristics of a bidirectional thrust bearing in a pumped storage, considering the effect of the thermal elastic…
Abstract
Purpose
The purpose of this paper is to analyze lubrication characteristics of a bidirectional thrust bearing in a pumped storage, considering the effect of the thermal elastic deformation of the pad and collar.
Design/methodology/approach
This study used the fluid–solid interaction (FSI) technique to investigate the lubrication characteristics of a bidirectional thrust bearing for several typical operating conditions. The influences of the operating conditions and the thrust load on the lubrication characteristics were analyzed. Then, various pivot eccentricities were investigated to analyze the effects of the pivot position.
Findings
It is found that the effect of the radial tilt angle of the collar runner on the oil film is compensated for by the radial tilt of the pad. The central pivot support system is the main factor limiting the loads of bidirectional thrust bearings.
Originality/value
This paper has preliminarily revealed the lubrication mechanism of bidirectional tilting-pad thrust bearings. A three-dimensional FSI method is suggested to evaluate the thermal–elastic–hydrodynamic deformations of thrust bearings instead of the conventional method, which iteratively solves the Reynolds equation, the energy equation, the heat conduction equation and the elastic equilibrium equation.
Details
Keywords
Amin Rahmat, Mostafa Barigou and Alessio Alexiadis
The purpose of this paper is to numerically study the dissolution of solid particles using the smoothed particle hydrodynamics (SPH) method.
Abstract
Purpose
The purpose of this paper is to numerically study the dissolution of solid particles using the smoothed particle hydrodynamics (SPH) method.
Design/methodology/approach
To implement dissolution, an advection–diffusion mass transport equation is solved over computational particles. Subsequently, these particles disintegrate from the solute when their concentration falls below a certain threshold.
Findings
It is shown that the implementation of dissolution is in good agreement with available data in the literature. The dissolution of solid particles is studied for a wide range of Reynolds and Schmidt numbers. Two-dimensional (2D) results are compared with three-dimensional (3D) cases to identify where 2D results are accurate for modelling 3D dissolution phenomena.
Originality/value
The present numerical model is capable of addressing related problems in pharmaceutical, biochemical, food processing and detergent industries.
Details
Keywords
Amir Hossein Rabiee and Mostafa Esmaeili
This study aims to explore an active control strategy for attenuation of in-line and transverse flow-induced vibration (FIV) of two tandem-arranged circular cylinders.
Abstract
Purpose
This study aims to explore an active control strategy for attenuation of in-line and transverse flow-induced vibration (FIV) of two tandem-arranged circular cylinders.
Design/methodology/approach
The control system is based on the rotary oscillation of cylinders around their axis, which acts according to the lift coefficient feedback signal. The fluid-solid interaction simulations are performed for two velocity ratios (V_r = 5.5 and 7.5), three spacing ratios (L/D = 3.5, 5.5 and 7.5) and three different control cases. Cases 1 and 2, respectively, deal with the effect of rotary oscillation of front and rear cylinders, while Case 3 considers the effect of applied rotary oscillation to both cylinders.
Findings
The results show that in Case 3, the FIV of both cylinders is perfectly reduced, while in Case 2, only the vibration of rear cylinder is mitigated and no change is observed in the vortex-induced vibration of front cylinder. In Case 1, by rotary oscillation of the front cylinder, depending on the reduced velocity and the spacing ratio values, the transverse oscillation amplitude of the rear cylinder suppresses, remains unchanged and even increases under certain conditions. Hence, at every spacing ratio and reduced velocity, an independent controller system for each cylinder is necessary to guarantee a perfect vibration reduction of front and rear cylinders.
Originality/value
The current manuscript seeks to deploy a type of active rotary oscillating (ARO) controller to attenuate the FIV of two tandem-arranged cylinders placed on elastic supports. Three different cases are considered so as to understand the interaction of these cylinders regarding the rotary oscillation.
Details
Keywords
Jianhang Xu, Peng Li and Yiren Yang
The paper aims to develop an efficient data-driven modeling approach for the hydroelastic analysis of a semi-circular pipe conveying fluid with elastic end supports. Besides the…
Abstract
Purpose
The paper aims to develop an efficient data-driven modeling approach for the hydroelastic analysis of a semi-circular pipe conveying fluid with elastic end supports. Besides the structural displacement-dependent unsteady fluid force, the steady one related to structural initial configuration and the variable structural parameters (i.e. the variable support stiffness) are considered in the modeling.
Design/methodology/approach
The steady fluid force is treated as a pipe preload, and the elastically supported pipe-fluid model is dealt with as a prestressed hydroelastic system with variable parameters. To avoid repeated numerical simulations caused by parameter variation, structural and hydrodynamic reduced-order models (ROMs) instead of conventional computational structural dynamics (CSD) and computational fluid dynamics (CFD) solvers are utilized to produce data for the update of the structural, hydrodynamic and hydroelastic state-space equations. Radial basis function neural network (RBFNN), autoregressive with exogenous input (ARX) model as well as proper orthogonal decomposition (POD) algorithm are applied to modeling these two ROMs, and a hybrid framework is proposed to incorporate them.
Findings
The proposed approach is validated by comparing its predictions with theoretical solutions. When the steady fluid force is absent, the predictions agree well with the “inextensible theory”. The pipe always loses its stability via out-of-plane divergence first, regardless of the support stiffness. However, when steady fluid force is considered, the pipe remains stable throughout as flow speed increases, consistent with the “extensible theory”. These results not only verify the accuracy of the present modeling method but also indicate that the steady fluid force, rather than the extensibility of the pipe, is the leading factor for the differences between the in- and extensible theories.
Originality/value
The steady fluid force and the variable structural parameters are considered in the data-driven modeling of a hydroelastic system. Since there are no special restrictions on structural configuration, steady flow pattern and variable structural parameters, the proposed approach has strong portability and great potential application for other hydroelastic problems.
Details
Keywords
Farhoud Kalateh and Ali Koosheh
This paper aims to propose a new smoothed particle hydrodynamics (SPH)-finite element (FE) algorithm to study fluid–structure interaction (FSI) problems.
Abstract
Purpose
This paper aims to propose a new smoothed particle hydrodynamics (SPH)-finite element (FE) algorithm to study fluid–structure interaction (FSI) problems.
Design/methodology/approach
The fluid domain is discretized based on the theory of SPH), and solid part is solved through FE method, similar to other SPH-FE methods in the previous studies. Instead of master-slave technique, the interpolating (kernel) functions of immersed boundary method are implemented to couple fluid and solid domains. The procedure of modeling completely follows the classic IB framework where forces and velocities are transferred between interacting parts. Three benchmark FSI problems are simulated and the results are compared with those of similar numerical and experimental works.
Findings
The proposed SPH-FE algorithm with promising and acceptable results can be utilized as a reliable method to simulate FSI problems.
Originality/value
Contrary to most SPH-FE algorithms, the calculation of contact force is not required at interacting boundaries and no iterative process is proposed to calculate forces, velocities and positions at new time step.
Details
Keywords
Yajing Hu, Botong Li, Xinhui Si, Jing Zhu and Linyu Meng
Atherosclerosis tends to occur in the distinctive carotid sinus, leading to vascular stenosis and then causing death. The purpose of this paper is to investigate the effect of…
Abstract
Purpose
Atherosclerosis tends to occur in the distinctive carotid sinus, leading to vascular stenosis and then causing death. The purpose of this paper is to investigate the effect of sinus sizes, positions and hematocrit on blood flow dynamics and heat transfer by different numerical approaches.
Design/methodology/approach
The fluid flow and heat transfer in the carotid artery with three different sinus sizes, three different sinus locations and four different hematocrits are studied by both computational fluid dynamics (CFD) and fluid-structure interaction (FSI) methods. An ideal geometric model and temperature-dependent non-Newtonian viscosity are adopted, while the wall heat flux concerning convection, radiation and evaporation is used.
Findings
With increasing sinus size, the average velocity and temperature of the blood fluid decrease, and the area of time average wall shear stress (TAWSS)with small values decreases. As the distances between sinuses and bifurcation points increase, the average temperature and the maximum TAWSS decrease. Atherosclerosis is more likely to develop when the sinuses are enlarged, when the sinuses are far from bifurcation points, or when the hematocrit is relatively large or small. The probability of thrombosis forming and developing becomes larger when the sinus becomes larger and the hematocrit is small enough. The movement of the arterial wall obviously reduces the velocity of blood flow, blood temperature and WSS. This study also suggests that the elastic role of arterial walls cannot be ignored.
Originality/value
The hemodynamics of the internal carotid artery sinus in a carotid artery with a bifurcation structure have been investigated thoroughly, on which the impacts of many factors have been considered, including the non-Newtonian behavior of blood and empirical boundary conditions. The results when the FSI is considered and absent are compared.
Details
Keywords
This paper aims to study the performance of hydrostatic turntables by using fluid structure interaction (FSI) and thermal effect coupled model.
Abstract
Purpose
This paper aims to study the performance of hydrostatic turntables by using fluid structure interaction (FSI) and thermal effect coupled model.
Design/methodology/approach
A novel fluid-structure-thermal coupled model is set up to study the problem. The FSI technique and computational fluid dynamics (CFD) method are used by this new model, and the thermal effects are also considered. Hydrostatic turntables with different system parameters (oil supply pressure, oil recess depth and surface roughness) are studied under different working conditions (rotational speeds of turntable and exerted external loads). Performance characteristics obtained from this FSI-thermal coupled model and conventional model are presented and compared.
Findings
Theoretical predictions are in good agreement with the experimental data. The results of new FSI-thermal coupled model are more accurate than those of the old conventional model. To acquire better performance of the system, the novel FSI-thermal model becomes necessary for different hydrostatic turntable systems.
Originality/value
This developed model is a useful tool for studying hydrostatic turntables. To get an improved performance, a proper selection of design parameters of the system based on FSI-thermal model is essential.
Details