3D Fluid-structure Interaction Research Articles

Investigation of crystalline lens overshooting: ex vivo experiment and optomechanical simulation results.

Introduction: Crystalline lens overshooting refers to a situation in which the lens momentarily shifts too much from its typical location immediately after stopping the rotational movement of the eye globe. This movement can be observed using an optical technique called Purkinje imaging. Methods: In this work, an experimental setup was designed to reproduce this effect ex vivo using a fresh porcine eye. The sample was rotated 90° around its centroid using a high-velocity rotation stage, and the Purkinje image sequences were recorded, allowing us to quantify the overshooting effect. The numerical part of the study consisted of developing a computational model of the eye, based on the finite element method, that allowed us to understand the biomechanical behavior of the different tissues in this dynamic scenario. A 2D fluid-structure interaction model of the porcine eye globe, considering both the solid parts and humors, was created to reproduce the experimental outcomes. Results: Outputs of the simulation were analyzed using an optical simulation software package to assess whether the mechanical model behaves optically like the real ex vivo eye. The simulation predicted the experimental results by carefully adjusting the mechanical properties of the zonular fibers and the damping factor. Conclusion: This study effectively demonstrates the importance of characterizing the dynamic mechanical properties of the eye tissues to properly comprehend and predict the overshooting effect.

Investigating a hermetic reciprocating compressor performance under variable lift limiter height using FSI method

This study examines discharge line energy losses using advanced fluid-structure interaction methods to show how valve design parameters—length, thickness, and height—improve compressor performance. An innovative 3D fluid-structure Interaction model represents a self-acting hermetic reciprocating compressor's discharge valve as a beam element. The RNG k− ε model examines how reed valve thickness, length, compressor speed, and lift limiter height impact pressure pulsation and compressor efficiency. Under ASHRAE conditions, operating at a challenging temperature range of 54.4 to −23.3 °C, the study meticulously explores the intricate interplay of discharge valve characteristics. Specifically, varying valve thicknesses (0.127, 0.152, 0.178, and 0.2 mm) and lengths (14.722, 16.222, and 17.722 mm) are examined in conjunction with different compressor speeds (1300, 2100, and 3000 rpm) according to the design specifications. Upon meticulous examination of discharge line losses at a compressor speed of 1300 rpm, intriguing insights emerged. For lift limiter heights of 0.8, 1.05, and 1.25 mm, coupled with a valve length of 17.722 mm, the study unveiled remarkable average energy losses of −6.91%, 2.83%, and −8.52%, respectively. The exploration continued at 2100 rpm, revealing a dynamic pattern with average losses for the same lift limiter heights at 0.94%, −1.26%, and −4.43%, respectively. In a succinct summary, the valve in focus demonstrated a noteworthy disparity in discharge line losses, reaching a maximum variation of 9.15%, −3.83%, and −8.30% when operated at the challenging speed of 3000 rpm.

A parametric study regarding structural design of a bioprosthetic aortic valve by 3D fluid-structure interaction simulations

Since the introduction of transcatheter aortic valve (AV) implantation as a viable option, surgical bioprosthetic AVs have recently started incorporating shorter struts considering future valve-in-valve procedures. However, the effect of leaflet coaptation geometry on the longevity of these valves remains unexplored. To address this gap, we performed a finite element analysis on bioprosthetic AVs with varying strut heights using a two-way fluid-structure interaction method. To establish a baseline, we used a standard height based on a rendered platform image of the CE PERIMOUNT Magna Ease valve from Edward Lifesciences in Irvine, CA. Bovine pericardium properties were assigned to the leaflets, while normal saline properties were used as the recirculating fluid in hemodynamic simulations. The physiological pressure profile of the cardiac cycle was applied between the aorta and left ventricle. We calculated blood flow velocity, effective orifice area (EOA), and mechanical stress on the leaflets. The results reveal that as the strut height increases, the stroke volume increases, leakage volume decreases, and EOA improves. Additionally, the maximum mechanical stress experienced by the leaflet decreases by 62% as the strut height increases to 1.2 times the standard height. This research highlights that a low-strut design in bioprosthetic AVs may negatively affect their durability, which can be useful in design of next-generation bioprosthetic AVs.

A Monte Carlo Sensitivity Analysis for a Dimensionally Reduced-Order Model of the Aortic Dissection.

Aortic dissection is associated with a high mortality rate. Although computational approaches have shed light on many aspects of the disease, a sensitivity analysis is required to determine the significance of different factors. Because of its complex geometry and high computational expense, the three-dimensional (3D) fluid-structure interaction (FSI) simulation is not a suitable approach for sensitivity analysis. We performed a Monte Carlo simulation (MCS) to investigate the sensitivity of hemodynamic quantities to the lumped parameters of our zero-dimensional (0D) model with numerically calculated lumped parameters. We performed local and global analyses on the effect of the model parameters on important hemodynamic quantities. The MCS showed that a larger lumped resistance value for the false lumen and the tears result in a higher retrograde flow rate in the false lumen (the coefficient of variation, [Formula: see text], the sensitivity [Formula: see text], Spearman's coefficient,[Formula: see text]). For the intraluminal pressure, our results show a significant role in the resistance and inertance of the true lumen (the coefficient of variation, [Formula: see text], the sensitivity [Formula: see text], and Spearman's coefficient,[Formula: see text] for the inertance of the true lumen). This study highlights the necessity of comparing the results of the local and global sensitivity analyses to understand the significance of multiple lumped parameters. Because of the efficiency of the method, our approach is potentially useful to investigate and analyze medical planning.

Time-Dependent Fluid-Structure Interaction Simulations of a Simplified Human Soft Palate.

Obstructive Sleep Apnea Syndrome (OSAS) is a common sleep-related disorder. It is characterized by recurrent partial or total collapse of pharyngeal upper airway accompanied by induced vibrations of the soft tissues (e.g., soft palate). The knowledge of the tissue behavior subject to a particular airflow is relevant for realistic clinic applications. However, in-vivo measurements are usually impractical. The goal of the present study is to develop a 3D fluid-structure interaction model for the human uvulopalatal system relevant to OSA based on simplified geometries under physiological conditions. Numerical simulations are performed to assess the influence of the different breathing conditions on the vibrational dynamics of the flexible structure. Meanwhile, the fluid patterns are investigated for the coupled fluid-structure system as well. Increasing the respiratory flow rate is shown to induce larger structural deformation. Vortex shedding induced resonance is not observed due to the large discrepancy between the flow oscillatory frequency and the natural frequency of the structure. The large deformation for symmetric breathing case under intensive respiration is mainly because of the positive feedback from the pressure differences on the top and the bottom surfaces of the structure.

A preliminary study of dynamic interactive simulation and computational CT scan of the ideal alveolus model.

While the development of CT imaging technique has brought cognition of in vivo organs, the resolution of CT images and their static characteristics have gradually become barriers of microscopic tissue research. Previous research used the finite element method to study the airflow and gas exchange in the alveolus and acinar to show the fate of inhaled aerosols and studied the diffusive, convective, and sedimentation mechanisms. Our study combines these techniques with CT scan simulation to study the mechanisms of respiratory movement and its imaging appearance. We use 3D fluid-structure interaction simulation to study the movement of an ideal alveolus under regular and forced breathing situations and ill alveoli with different tissue elasticities. Additionally, we use the Monte Carlo algorithm within the OpenGATE platform to simulate the computational CT images of the dynamic process with different designated resolutions. The resolutions show the relationship between the kinematic model of the human alveolus and its imaging appearance. The results show that the alveolus and the wall thickness can be seen with an image resolution smaller than 15.6μm. With ordinary CT resolution, the alveolus is expressed with four voxels. This is a preliminary study concerning the imaging appearance of the dynamic alveolus model. This technique will be used to study the imaging appearance of the dynamic bronchial tree and the lung lobe models in the future.

Analysis of the immersed boundary method for turbulent fluid-structure interaction with Lattice Boltzmann method

An efficient and new methodology to deal with fluid structure interaction at high Reynolds number flows is presented in this article. It relies on the coupling of the lattice Boltzmann method and the immersed boundary method with a second order predictor corrector model for the structure. The effect of the lagrangian weight of the immersed boundary method is also analyzed in the context of fluid structure interaction. Both curved and moving boundaries are considered, and several methods to calculate the lagrangian weight are compared on relevant test-cases: the laminar flow around a cylinder at Reynolds number Re=100, the Poiseuille flow in a 2D channel and a 3D fluid-structure interaction test case: a deformable flapping flag immersed in a laminar flow. A convergence study in space and time is performed and the three following parameters are investigated: the number of lagrangian markers along the boundary, the value of the lagrangian weight and the shape of the discrete delta function used in the immersed boundary. Finally, the novelty of the paper is two-fold: a new expression of the lagrangian weight which is found to reduce the error by 20% in the case of fluid-structure interaction, and the coupling of a turbulence model with a second order predictor corrector model for improved stability and accuracy. This numerical methodology is found here to be accurate for challenging cases with high added mass effect and high Reynolds number flows.

A bar-joint model based on the corrected resistive force theory for artificial flagellated micro-swimmers propelled by acoustic waves

In this work, we proposed a bar-joint model based on the corrected resistive force theory (CRFT) for studying artificial flagellated micro-swimmers (AFMSs) propelled by acoustic waves in a two-dimensional (2D) flow field or with a rectangular cross-section. Note that the classical resistive-force theory for 3D cylindrical flagellum leads to over 90% deviation in terminal velocity from those of 2D fluid-structure interaction (FSI) simulations, while the proposed CRFT bar-joint model can reduce the deviation to below 5%; hence, it enables a reliable prediction of the 2D locomotion of an acoustically actuated AFMS with a rectangular cross-section, which is the case in some experiments. Introduced in the CRFT is a single correction factor K determined by comparing the linear terminal velocities under acoustic actuation obtained from the CRFT with those from simulations. After the determination of K, detailed comparisons of trajectories between the CRFT-based bar-joint AFMS model and the FSI simulation were presented, exhibiting an excellent consistency. Finally, a numerical demonstration of the purely acoustic or magneto-acoustic steering of an AFMS based on the CRFT was presented, which can be one of the choices for future AFMS-based precision therapy.

Research on mechanical behaviors of submarine pipeline inspection gauges in the elbow: FSI simulation and mathematic modeling

Pigs applied for submarine pipeline inspection and cleaning operations frequently suffer from blockage risk when passing through the elbow. It is meaningful to understand the frictional contact characteristics of the pig when it runs through the elbow, which helps improve the traveling ability of the pig. In this paper, a basic assumption that the trajectory of the mandrel geometric center coincides with the pipeline central axis is put forward according to the 3D Fluid-Structure Interaction (FSI) simulation results, and then a dynamic analytical model that predicts the driving force and describes the mechanical behaviors of cup pig in the straight pipeline and the elbow is respectively derived using a novel algorithm combined with the modified Burgers-Frenkel (MB-F) model. The established analytical model was calculated by means of MATLAB programming. Take a specific working condition as an example, and a quantitative assessment method was proposed. Based on the calculation results of the analytical model, the frictional contact characteristic of the pig in the elbow was studied, and the traveling performance and security of the pigging operation were further evaluated.

Regularity results in 2D fluid–structure interaction

We study the interaction of an incompressible fluid in two dimensions with an elastic structure yielding the moving boundary of the physical domain. The displacement of the structure is described by a linear viscoelastic beam equation. Our main result is the existence of a unique global strong solution. Previously, only the ideal case of a flat reference geometry was considered such that the structure can only move in vertical direction. We allow for a general geometric set-up, where the structure can even occupy the complete boundary. Our main tool—being of independent interest—is a maximal regularity estimate for the steady Stokes system in domains with minimal boundary regularity. In particular, we can control the velocity field in W2,2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$W^{2,2}$$\\end{document} in terms of a forcing in L2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$L^2$$\\end{document} provided the boundary belongs roughly to W3/2,2.\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$W^{3/2,2}.$$\\end{document} This is applied to the momentum equation in the moving domain (for a fixed time) with the material derivative as right-hand side. Since the moving boundary belongs a priori only to the class W2,2,\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$W^{2,2},$$\\end{document} known results do not apply here as they require a C2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$C^2$$\\end{document}-boundary.

A three-dimensional fluid-structure interaction model based on SPH and lattice-spring method for simulating complex hydroelastic problems

The present work revolves around the development of a 3D particle-based Fluid-Structure Interaction (FSI) solver to simulate hydroelastic problems that involve free surface. The three-dimensional Volume-Compensated Particle Method (VCPM) for modelling deformable solid bodies is developed within the open-source SPH software package DualSPHysics. Complex 3D FSI problems are readily simulated within a reasonable time frame thanks to the parallel scalability of DualSPHysics on both CPU and GPU. The Sequential Staggered (SS) scheme paired with a multiple time-stepping procedure is implemented in DualSPHysics for coupling the SPH and VCPM models. It is found that the SPH-VCPM method is computationally more efficient than the previously reported SPH-TLSPH method. Extensive validations have been performed based on some very recent 3D experimental setups that involve violent free surface and complex structural dynamics. Findings from this research highlight the capability of the 3D SPH-VCPM model to reproduce some of the physical observations that were not captured by previous 2D studies. Some preliminary 3D FSI results involving solid fracture are also demonstrated.

Fluid structure computational model of simulating mitral valve motion in a contracting left ventricle

Background:Fluid structure interaction simulations h hold promise in studying normal and abnormal cardiac function, including the effect of fluid dynamics on mitral valve (MV) leaflet motion. The goal of this study was to develop a 3D fluid structure interaction computational model to simulate bileaflet MV when interacting with blood motion in left ventricle (LV). Methods:The model consists of ideal geometric-shaped MV leaflets and the LV, with MV dimensions based on human anatomical measurements. An experimentally-based hyperelastic isotropic material was used to model the mechanical behaviour of the MV leaflets, with chordae tendineae and papillary muscle tips also incorporated. LV myocardial tissue was prescribed using a transverse isotropic hyperelastic formulation. Incompressible Navier–Stokes fluid formulations were used to govern the blood motion, and the Arbitrary Lagrangian Eulerian (ALE) method was employed to determine the mesh deformation of the fluid and solid domains due to trans-valvular pressure on MV boundaries and the resulting leaflet movement. Results:The LV–MV generic model was able to reproduce physiological MV leaflet opening and closing profiles resulting from the time-varying atrial and ventricular pressures, as well as simulating normal and prolapsed MV states. Additionally, the model was able to simulate blood flow patterns after insertion of a prosthetic MV with and without left ventricular outflow tract flow obstruction. In the MV–LV normal model, the regurgitant blood flow fraction was 10.1 %, with no abnormality in cardiac function according to the mitral regurgitation severity grades reported by the American Society of Echocardiography. Conclusion:Our simulation approach provides insights into intraventricular fluid dynamics in a contracting LV with normal and prolapsed MV function, as well as aiding in the understanding of possible complications after transcatheter MV implantation prior to clinical trials.

3D fluid–structure interaction with fracturing: A new method with applications

This paper presents a methodology for simulating general, three-dimensional fluid–structure interaction problems involving fracturing. Ordinary state-based peridynamics is used to describe the mechanical behaviour of the solid phase in a Lagrangian framework. The governing equations of peridynamics are coupled via a multi-direct immersed boundary method with the incompressible formulation of the Navier–Stokes equations, which are used to govern the dynamics of the fluid phase. The synchronization of the solution is achieved via a fully explicit, weak-coupling strategy that allows for fast and efficient computations. A detailed description of the methodology is provided, together with the results of several validation benchmarks. The qualitative results of the unsteady hydraulic fracture of a porous medium are also presented to show the potential of the proposed approach. The authors believe that the numerical technique described in this paper contributes to advance the capability of models in reproducing complex fluid–structure interaction and hydraulic fracture problems, providing a very detailed description of both the fluid and solid mechanics of the processes involved.

Distributed lumped parameter modeling of blood flow in compliant vessels

We extend our previous distributed lumped parameter (DLP) modeling approach to take into account blood vessel wall deformability. This is achieved by adding a compliance term for each vascular segment based on 1D NS equations. The results of the proposed method are compared against 1D Navier–Stokes and 3D fluid–structure interaction (FSI) modeling in idealized and patient-specific models. We show that 1D Navier–Stokes blood flow modeling can be highly inaccurate in predicting flow and pressure dynamics in diseased cases, while in comparison the DLP approach produces consistently accurate flow and pressure waveforms as compared to 3D FSI modeling. The relative accuracy and computational efficiency of the proposed DLP approach offer the possibility to replace or augment 1D or 3D modeling to study hemodynamics in a variety of applications.

A Numerical Study on Mechanical Seal Dynamic Characteristics Within a Reactor Coolant Pump

Unstable flow within a reactor coolant pump (RCP)’s mechanical seal may cause the change of its sealing parameters, possibly threatening RCP’s safe operations. In this study, based on the moving grid technology, a 3D fluid–structure interaction analysis model is established, where the influence of parameters such as the inlet pressure fluctuation, closing force fluctuation, and speed fluctuation on mechanical seal performance characteristics within an RCP is numerically studied. Study results have shown that when pressure and closing force fluctuations are applied, the static ring displacement, the inlet-to-outlet temperature difference, and the leakage difference show similar variational rules. In addition, it is found that the sealing parameters are more sensitive to the step form of fluctuation. When the step change of 4% closing force was applied, the static ring displacement was more than 36.7%, the change of the temperature difference between inlet and outlet zones exceeded 53.5%, and the leakage difference was more than 127.2%. The change of speed has also been found to significantly affect the temperature difference between the RCP mechanical seal’s inlet and outlet, but the effect on the leakage and opening force was negligible.

The internal substructure method for shock wave input in 2D fluid-structure interaction analysis with unbounded domain using doubly-asymptotic ABC

Interaction between underwater shock waves and structures has attracted significant interest of many researchers. This study aims to develop a method to solve two-dimensional (2 D) fluid-structure interaction problems during far-field underwater explosion (UNDEX). The acoustic domain which can undergo small pressure variations is considered to describe the fluid-structure interaction during UNDEX. First, the empirical formula of the incident shock waves is considered as free wave motion of the fluid, and the fluid domain is Discretized by the finite element method. Based on the scaled boundary finite element method (SBFEM) and continued fraction solution, an artificial boundary condition (ABC) with high accuracy in time domain is adopted to simulate the truncated infinite domain, which can be placed very close to the radiating field is adopted to simulate the truncated infinite domain. Third, an internal substructure method (ISM) to calculate the equivalent input shock wave loads is proposed. Finally, the proposed method is used to study the scattered waves on a rigid circular structure due to the shock wave, and the effect of the radiation wave due to the motion of the structure on the dynamic responses of the circular structure during UNDEX is studied.

Water entry dynamic analysis of lightweight sandwich plates with lattice core: A semi-analytical approach and comparative study

This is the third part of water entry hydro-elastic analysis of clamped sandwich plates with lattice core (CSPLC). In the first and second parts analysis, the engineering prediction model is built to estimate the dynamic responses of CSPLC. To discuss the responses of CSPLC in more detail, the objective of the present work is to investigate the hydro-elastic responses of rectangular, clamped sandwich plates with lattice core (CSPLC) subjected to water entry via combined a novel semi-analytical approach and multi-physical numerical simulation. In the theoretical approach, the hydro-elastic characteristics are quantified by coupling a hydrodynamic water entry model with a first shear displacement model of elasticity for CSPLC. The fluid-structure interaction (FSI) effects of water entry are taken into account by dividing the total impact pressure into the rigid water entry pressure and the interacting pressure. To capture the precise responses of CSPLC, both the global displacement field and the local displacement field are considered in the analytical model. The dynamic governing equations are derived from the energy variation principle and solved by employing the modal approach. Furthermore, the 3D FSI finite element simulation is carried out to get the detailed hydro-elastic characteristics of CSPLC. This engineering semi-analytical model is found to yield accurate results for dynamic responses and offers significant savings in computational cost compared to the FSI simulations. As a comparative study, for a same geometrical stiffened panel, the FSI impact pressure and structural deflection are also given respectively.

Accurate Calculation of FFR Based on a Physics-Driven Fluid‐Structure Interaction Model

Background: The conventional FFRct numerical calculation method uses a model with a multi-scale geometry based upon CFD, and rigid walls. Therefore, important interactions between the elastic vessel wall and blood flow are not routinely considered. Changes in the resistance of coronary microcirculation during hyperaemia are likewise not typically incorporated using a fluid–structure interaction (FSI) algorithm. It is likely that both have resulted in FFRct calculation errors. Objective: In this study we incorporated both the influence of vascular elasticity and coronary microcirculatory structure on FFR, to improve the accuracy of FFRct calculation. Thus, in this study, a physics-driven 3D–0D coupled model including fluid–structure interaction was established to calculate accurate FFRct values. Methods: Based upon a novel geometric multi-scale modeling technology, a FSI simulation approach was used. A lumped parameter model (0D) was used as the outlet boundary condition for the 3D FSI coronary artery model to incorporate physiological microcirculation, with bidirectional coupling between the two models. Results: The accuracy, sensitivity, specificity, and both positive and negative predictive values of FFRDC calculated based upon the coupled 3D–0D model were 86.7, 66.7, 84.6, 66.7, and 91.7%, respectively. Compared to the calculated value using the basic CFD model (MSE = 5.9%, accuracy rate = 80%), the FFRCFD calculated based on the coupled 3D–0D model has a smaller MSE of 1.9%. Conclusion: The physics-driven coupled 3D–0D model that incorporates fluid–structure interactions not only consider the influence of the elastic vessel wall on blood flow, but also provides reliable microvascular resistance boundary conditions for the 3D FSI model. This allows for a calculation that is based upon conditions that are closer to the physiological environment, and thus improves the accuracy of FFRct calculation. It is likely that more accurate information will provide an enhanced recommendation regarding percutaneous coronary intervention (PCI) in the clinic.

Using a reduced-order model to investigate the effect of the heart rate on the aortic dissection.

The computational cost of a three-dimensional (3D) fluid-structure interaction (FSI) simulation of a dissected aorta has prevented researchers from investigating the effect of a wide range of the heart rate on the hemodynamic quantities in the disease. We have presented a systematic procedure to develop a zero-dimensional (0D) model for a dissected aorta. A series of numerical experiments were used to calculate the values for the resistance, inertance, and compliance of each lumen with irregular geometries. Having validated the results from the 0D model against those from the 3D model for one heart rate, we used the 0D model to investigate the effect of the heart rate of 50-150 bpm on the flow rates and the pressures in an idealized geometry of an aortic dissection. The 0D model showed acceptable accuracy when compared with the 3D FSI simulation. For instance, at peak systole, 7.18% relative error in the flow rate in the true lumen was observed for 0D and 3D simulations. The flow rate in the true lumen showed a stronger dependency on the heart rate, that is, 300% for the true lumen and 1.5% for the false lumen. The pressure difference between the lumina increased non-monotonically as the heart beats faster. Because of its efficiency, the reported procedure can be used for uncertainty and sensitivity analysis of the hemodynamic quantities in a diseased aorta with complex geometries such as that of the aortic dissection.

Mechanical behaviors of pipeline inspection gauge (pig) in launching process based on Coupled Eulerian-Lagrangian (CEL) method

Successful launching of the pig is the premise for ensuring the efficiency and accuracy of the pigging operation. This study investigates the effect of the flow field on pig launching by the three-dimensional (3D) fluid-structure interaction (FSI) model based on the Coupled Eulerian-Lagrangian (CEL) method for the first time. Besides, the flow field experiment and the dragging experiment are conducted to verify the reliability of the simulation results. Four parameters as friction force, mandrel flip angle, pig velocity, cup deformation are selected to describe the mechanical behaviors of the pig. Research results indicate that the flow field has a significant effect on contact behaviors between the pig and the pipeline in the pig running-in stage but less effect on that in the steady stage, which presents the necessity of the FSI simulation for investigating the pig launching process.