FSI Approach Research Articles

An effective parametric sensitivity analysis to improve electrical and thermal energy/exergy efficiency of PVT system using nanofluid

A 3D steady-state model of a photovoltaic/Thermal system with nanofluid is studied to investigate the electrical and thermal performance of PVT by utilizing a combination of statistical modeling and numerical simulation. The 3D CAD (Computer Aided Design) modeling of the photovoltaic thermal (PV/T) is performed using Ansys Space Claim. The current study is based on using a 2-way coupling FSI approach for modeling nanofluid-based PVT systems. Five output responses electrical power, thermal power, electrical exergy, thermal exergy, and entropy generation are chosen against four input parameters, solar radiation (G_sun), ambient temperature (Tamb), mass flow rate (ṁ), and nanoparticles concentration % (φ) to analyze system performance. A statistical prediction model is developed using response surface methodology (RSM) that starts from the design of experiment (DOE). The predicted outcomes obtained from the statistical model and the numerical simulation of the heat transfer model exhibit the existence of good fitness. Furthermore, optimization is performed using RSM for various optimization objectives to suggest the ideal design parameter values for optimal system performance. Sensitivity analysis illustrates that a rise in ambient temperature causes a drop in electrical power production and leads to an increase in thermal power. However, the increase in solar radiation boosts electrical power and causes a drop in thermal exergy, entropy generation increases with an increase in solar irradiation. Similarly, an increase in mass flow rate leads to an increase in thermal power. Multi-objective optimization with the highest composite desirability values depicts the influence of input design parameters and has a favorable effect on the objective of concurrently maximizing electrical and thermal power.

Comparative Analysis of Aerodynamic and Structural Performance of Aircraft Wings Using Boron Aluminum Metal Matrix Composites and Aluminum Alloys: A CFD and FSI Approach

Comparative Analysis of Aerodynamic and Structural Performance of Aircraft Wings Using Boron Aluminum Metal Matrix Composites and Aluminum Alloys: A CFD and FSI Approach

Numerical Research on Impacting Load and Structural Response for a Model Experiment of High-speed Craft

Abstract High-speed craft generally applies hy droplane boat-type and large power engine to obtain high speed in water as results that significant hydrodynamic nonlinearities, high-speed craft has complex the impact load characteristics and structural response which attract considerable attentions of ship mechanics researchers. This paper studies impacting load and structural response of a high-speed craft by means of numerical approach coupling CFD and FEM. A model experiment of high-speed craft is selected to simulate impact load and structural response, the craft model consists of two ship bodies and a keel beam, a number of pressure sensors and strain gauges are arranged to capture the impacting pres s ure and VBM. A numerical FSI approach coupling CFD and FEM is used to study the model experiment of the high-speed craft. CFD is used to solve the hydrodynamics of the high-speed craft, DFBI and overset grid algorithm are employed to simulate the craft motion. Dy namic FEM is us ed to calculate structural response of high-speed craft, structural VBM is obtained. Two-way FSI is employ ed to realize coupling of CFD and FEM, wave pres s ures and structural displacement are iterated to progress. At last, numerical res ults and experimental res ults including impacting pressure, craft motion and VBM are compared and analyzed, they agree with closely. The numerical approach can be used to study the impacting load and structural respons e for high-speed craft.

Detailed Structural Analysis of Cylindrical Steel Tank Subjected to Various Seismic Peak Ground Values Using FSI Approach

The seismic analysis of ground-supported cylindrical steel tanks subjected to lateral harmonic displacement loadings has been carried out. This paper numerically evaluates the structural response of various tank geometries due to resonant seismic sloshing. The numerical investigation is performed using a two-way fluid structural interaction approach that couples computational fluid dynamics analysis with finite element transient structural analysis. The results of the analysis have been validated using Seismic Design Code (Eurocode 8, part 4). Regarding tank aspect ratio (H/D), five geometries covering slender, medium, and broad structures are analyzed under ten harmonic base excitations. All the geometries are excited at their first convective frequency, whose shape and magnitude are evaluated using modal analysis. The seismic response curves have been developed for each tank model, which reveal the complex and peculiar structural response. It is observed from the tanks’ seismic response that they undergo three transitional stress zones named safe, yielding, and failure zones. The critical loadings and failure duration have also been evaluated for each tank model. This will help to avoid future structural damage by designing liquid-containing structures based on evaluated seismic failure loads.

Numerical Approach for The Evaluation of Hemodynamic Behaviour in Peripheral Arterial Disease: A Systematic Review

Reduced blood flow to the lower extremities causes peripheral arterial disease (PAD), which is caused by atherosclerotic plaque in the arterial wall. If this impairment is not treated, it will result in severe vascular diseases like ulceration and gangrene. Previous research has shown that while evaluating the pathology of the peripheral artery, the assumption of the model geometry significantly impacts the uncertainty of the stenosis area. However, more work needs to be done to understand the interaction between mechanical better and flow conditions in the peripheral artery using a separate computer model of the cardiovascular system. This paper reviews the numerical approach on pre- and post-treatment of hemodynamic behavior in peripheral arterial disease (PAD). The goal of this study was to thoroughly examine the most recent developments with the application of computational studies in PAD from 2017 to 2022. While FSI investigation highlights the behavior of both the fluid and structure domains (blood and artery) during the numerical analysis of blood flow, CFD simulations primarily focus on the fluid domain (blood) behavior. Out of 92 research publications, 19 were appropriate for this assignment. This thorough study divides the publications into the categories of CFD, and FSI approaches. The results were then reviewed in accordance with the wall characteristic, analytical method, geometry, viscosity models, and validation. This paper summarizes the parameters of geometrical construction, viscosity models, analysis methods, and wall characteristics taken into consideration by the researchers to identify and simulate the blood flood flow in the stenosis area. These parameters are summarised in this study. Additionally, it could offer systematic data to help future studies produce better computational analyses.

Modelling of thrombus formation using smoothed particle hydrodynamics method.

In this paper a novel model, based on the smoothed particle hydrodynamics (SPH) method, is proposed to simulate thrombus formation. This describes the main phases of the coagulative cascade through the balance of four biochemical species and three type of platelets. SPH particles can switch from fluid to solid phase when specific biochemical and physical conditions are satisfied. The interaction between blood and the forming blood clot is easily handled by an innovative monolithic FSI approach. Fluid-solid coupling is modelled by introducing elastic binds between solid particles, without requiring detention and management of the interface between the two media. The proposed model is able to realistically reproduce the thromboembolic process, as confirmed by the comparison of numerical results with experimental data available in the literature.

Novel design of natural solar air heat for higher thermal performance utilizing porous vortex generator

In this study, the thermal performance of a 2-D turbulent natural convection airflow inside a solar air heater is improved by using a flexible porous vortex generator, which is a self-sustained passive oscillator. The inclined thin elastic porous winglet, used as vortex generator, is attached on the heated wall for flow mixing and convection enhancement. Ongoing vortices, due to the resultant fluid–structure interaction, disrupts the thermal boundary layer, which then leads to the mixing process and improving the heater’s performance. Using a porous vortex generator, instead of its main competitor, the solid winglet, not only decreases the blockage effect and causes a higher airflow rate, but also results in a higher mean outlet-temperature by more mixing rate. To demonstrate the benefits of this idea, a numerical simulation considering a two-way strongly-coupled FSI approach in transient condition is done. The present numerical results are validated against the experimental and numerical data. It’s found that employing porous vortex generator confers considerable performance enhancement up to 500% on air temperature increase respect to the conventional clear solar air heater (from 8 to 40.5 °C) while providing a higher airflow rate 8.3% and outlet-temperature (135%) in comparison with solid winglet. This study aims to make the renewable thermal-solar system more efficient and affordable so that the industrial society will become more interested toward sustainable infrastructure.

코리올리 유량계의 정밀설계를 위한 수치해석적 성능 예측

A theoretical and numerical FSI approach is used to predict the mass flow in a Coriolis flow meter. By comparing with the experimental results according to the relationship between mass flow and the time phase difference at the inlet and outlet of the tubes, the authors could determine the reliability of the present results from a theoretical and numerical approach in this paper. The mass flow has a linear relationship with the time phase difference, which is a unique parameter to measure true mass flow; therefore, for more precise measurement, it should be long enough to detect the signal within the given time resolution afforded by the detecting system and control system. Compact size and manufacturability, which are the important factors that decide the product competitiveness, should also be considered. In this paper, inversed triangle shaped and conventional U shaped Coriolis flow meters are designed, their time phase difference performances are predicted, and the results from experiments are well matched with the predicted results from the above-mentioned analysis.

A distributed lumped parameter model of blood flow with fluid-structure interaction.

A distributed lumped parameter (DLP) model of blood flow was recently developed that can be simulated in minutes while still incorporating complex sources of energy dissipation in blood vessels. The aim of this work was to extend the previous DLP modeling framework to include fluid-structure interactions (DLP-FSI). This was done by using a simple compliance term to calculate pressure that does not increase the simulation complexity of the original DLP models. Verification and validation studies found DLP-FSI simulations had good agreement compared to analytical solutions of the wave equations, experimental measurements of pulsatile flow in elastic tubes, and in vivo MRI measurements of thoracic aortic flow. This new development of DLP-FSI allows for significantly improved computational efficiency of FSI simulations compared to FSI approaches that solve the full 3D conservation of mass and momentum equations while also including the complex sources of energy dissipation occurring in cardiovascular flows that other simplified models neglect.

Structural Assessment of a Cylindrical Liquid Tank due to Shape Change of Roof during Sloshing Induced by Seismic Activity

The structural behavior of ground supported upright cylindrical fluid tank subjected to lateral excitations due to the seismic effects is presented by considering both below and convective resonance scenarios using the FSI approach. The study of seismic response has been carried out at an actual scale on a typical API Tank of 23,000 gallons capacity. In response to seismic excitations with peak acceleration of 0.3 g, the sloshing phenomena have been studied at three fill levels. For minimizing the roof stresses in the API tank due to seismic sloshing, the roof design is modified by varying roof angles starting from flat to 30° conical roof angles with an increment of 10°. It is found that for flat roof steel tank operating at convective resonance, stress increases exponentially with the fill level resulting in tank yielding. To increase tank seismic resistance, a self-supported conical roof (SSCR) of various angles is considered. The effect of variation of SSCR angle and slenderness ratio on structural response has been studied. Using the design by analysis approach, empirical relationships for estimation of tank structural strength (TSS) and total deformations have been proposed. It is concluded that the TSS is increased up to 6 times by selecting an appropriate conical roof (30°).

Fully coupled dynamic simulations of bioprosthetic aortic valves based on an embedded strategy for fluid-structure interaction with contact.

This work aims at presenting a fully coupled approach for the numerical solution of contact problems between multiple elastic structures immersed in a fluid flow. The key features of the computational model are (i) a fully coupled fluid-structure interaction with contact, (ii) the use of a fibre-reinforced material for the leaflets, (iii) a stent, and (iv) a compliant aortic root. The computational model takes inspiration from the immersed boundary techniques and allows the numerical simulation of the blood-tissue interaction of bioprosthetic heart valves (BHVs) as well as the contact among the leaflets. First, we present pure mechanical simulations, where blood is neglected, to assess the performance of different material properties and valve designs. Secondly, fully coupled fluid-structure interaction simulations are employed to analyse the combination of haemodynamic and mechanical characteristics. The isotropic leaflet tissue experiences high-stress values compared to the fibre-reinforced material model. Moreover, elongated leaflets show a stress concentration close to the base of the stent. We observe a fully developed flow at the systolic stage of the heartbeat. On the other hand, flow recirculation appears along the aortic wall during diastole. The presented FSI approach can be used for analysing the mechanical and haemodynamic performance of a BHV. Our study suggests that stresses concentrate in the regions where leaflets are attached to the stent and in the portion of the aortic root where the BHV is placed. The results from this study may inspire new BHV designs that can provide a better stress distribution.

MODELLING THE SHOCK ABSORBER PISTON VALVE USING 2-WAY FLUID-STRUCTURE INTERACTION

The aim of this study is to examine the strongly coupled Fluid-Structure Interaction approach as a comprehensive method of predicting the performance of the shock absorber piston valve. For this purpose, numerical simulation sand experimental testing are carried out. The coupled CFD-FEA numerical model described in this article, contrary to the attempts made so far, takes into account the influence of contact between valve discs and the initial conditions of the disc stack preload. The model is based on the actual valve geometry used in the shock absorber design. As a result, the described approach is intended for use in industrial applications in development works, in particular, at the conceptual stage. To prove the reliability of the model, two valve compositions are chosen to be measured on a test bench and modelled in FSI simulations. For both of them, a satisfactory level of correlation is achieved, with the correlation error below 10% and well-predicted valve opening points. As a result, it is proved that the 2- way FSI approach has great potential to be successfully used to investigate the damper valve operation.

Comparison of acoustic-structure based one-way FSI and two-way FSI

In the numerical simulation of flow-induced vibration using two-way fluid-structure interaction (TW-FSI) method, it is usually limited by mesh deformation, and consumes a lot of computing resources. These problems can be avoided by adopting acoustic-structure based one-way FSI (ASOW-FSI) approach. The purpose of this work is to explore the applicability of ASOW-FSI, and to analyze the similarities and differences between the two dynamic response analysis methods. A series of numerical calculations are carried out for the elastically mounted rigid cylinder at low Reynolds number. By systematically comparing the results calculated by these two methods, we found that ASOW-FSI can accurately predict the response in the range of partial reduced velocity, even closer to the experimental results than TW-FSI method. The main reason for the difference between the two methods in the whole reduced velocity range is that the ASOW-FSI method can not predict the “lock-in”. Finally, the mechanism of “lock-in” in vortex-induced vibration (VIV) is analyzed by forced oscillation. The results show that the structural vibration has the ability to dominate the vortex shedding under certain conditions. If the natural mode of the structure is excited at this time, “lock-in” will occur.

Fluid - structure interaction analyze for the centrifugal compressor 3d impellers

The article deals with the issues of the 3D impellers strength analysis for the different centrifugal compressors. Two air compressors are considered, the first for General industrial use, the second for turbocharging the internal combustion engine. The third compressor is designed for the turboexpander unit that operating at high pressure medium. The materials of the impellers were steel, titanium and aluminum alloys. The expediency of using the Fluid-Structure Interaction approach for the strength analysis is considered for these compressors. With the FSI approach, a coupled CFD-FEA solution is performed. Gas-dynamic forces from the medium pressure are taken into account in the impeller strength or vibration analysis. The Ansys package is selected as the program for analysis. CFD models are built and configured in the Ansys CFX. The FEA solution carried out in the Ansys Static structural. The results of strength analysis are compared with and without pressure forces for all impellers. As a result, there were no significant differences in the two solutions for the air compressors. However, for high-pressure compressors, the results of the coupled solution showed the need to take into account the CFD solution. Based on the obtained data, a graph of the reliability coefficient dependence on the increase in the suction pressure in the range from 1 to 100 bar is plotted.

Evaluation of the ocular fluid dynamic effects on intraocular magnesium-based device: A comparison between CFD and FSI approaches

Magnesium is an essential element for the ocular functions and used for the realization of medical devices due to its low corrosion resistance, bioresorbable nature and biocompatibility. Wet age-related macular degeneration is one of the main causes of blindness with patients treated by intravitreal injections of inhibitor drugs. According to the need to reduce the number of injections, the development of new drug delivery devices able to extend the therapeutical outcomes is mandatory and magnesium can be considered as a promising candidate. The aim of the work concerns the evaluation of the ocular fluid dynamic role on a magnesium-based device placed in the vitreous chamber. Particularly, the fluid-induced shear stress field on the surfaces in contact with the liquefied vitreous was studied. Both computational fluid dynamic and fluid-structure interaction approaches were proposed and then compared. Saccadic motion was implemented to recreate the vitreous fluid dynamics. High changes in terms of fluid-induced shear stress field varying the CFD and FSI numerical approaches and kinematic parameters of the saccadic function can be noticed. The comparison between CFD and FSI approaches showed minor significant differences and both implementations suggested the possibility to obtain a uniform and controlled corrosion of the device.

Nuclear Fuel Assembly Deformation, Reduced Mechanical Model Dedicated to FSI Simulation

In the pressure vessel of a PWR the core is constituted of a number of fuel assemblies. Under operation, they all suffer from various phenomena, among them, initial trapped efforts, thermal expansion, irradiation growth, creeping, tightening relaxation and rod slipping. Each fuel assembly may develop contacts with its neighbors and strongly interacts with the fluid. It then undergoes vertical as well as lateral fluid forces, which are partly coupled with its instantaneous shape. As a consequence the fuel assembly tends to get distorted during and still after operation. The first concern is economic: at the end of a cycle, when changing the assembly position in the core, the contact interactions with its neighbors due to its distorted shape sometimes delay the handling. The second concern is that the shutdown rods have to slide into the deformed shape of the guide tube and might be slowed due to excessive friction forces. In order to precisely assess these situations it is necessary to simulate numerically a complete core, taking into account all of the previously mentioned phenomena. For that purpose, we propose a light but relevant reduced mechanical model of a fuel assembly, partially based on a POD analysis performed on a detailed fuel assembly model. We then show that a rather simple model, still based on classical finite elements can be used and simplifies the integration of the local nonlinear constitutive equations. We then compare both of the detailed and reduced model on typical situations and show excellent agreement. The CPU time ratio between them, for a full nonlinear simulation of a single fuel assembly under operation, is over 1000, which is competitive against separation of variables based reduced order methods such as POD, PGD and even APHR. So, yet still with a simplified FSI approach, the drastic memory and CPU reductions obtained now enable us to complete a 3D core simulation representing at least 4 years under operation (4 cycles), with as much as 241 individual fuel assemblies, in a reasonable time of a few hours.

Wear study and EHD lubrication analysis on connecting rod big end bearings of off‐highway application engine

AbstractThe connecting rod big end bearings are under dynamic lubrication during working cycle, and in most of the time, the con rod is subjected to compressive stress. The conventional method of performing an EHL analysis on a bearing involves development of complex mathematical equations and simplification of actual physical model. This paper presents a methodology to model and simulate the elastohydrodynamic lubrication and wear study of connecting rod big end bearings of off‐highway application engine using the application of computational fluid dynamics (CFD) and computational structural dynamics (CSD) approaches. The pressure field for a full journal bearing operating under laminar flow regime with various eccentricities was obtained by CFD, and fluid pressure distribution and deformation in the bearing liner due to pressure were evaluated using FSI approach. Relevant parameters of lubrication characteristics were analyzed to optimize the eccentricity value. The maximum bearing load value of 21 kN was noticed at TDC position for the optimum eccentricity. The load distribution indicated critical points in the bearing, and the data obtained from bearing load and sliding velocity of journal were used in Archard's wear relation to determine the wear depth along the bearing width. The simulated wear results were compared with three‐cylinder off‐highway application engine con rod big end bearings, which ran for 1000 hours at full load condition, and satisfactory agreement was observed between experiment and simulation values.

Parametric investigation of surface texturing on performance characteristics of water lubricated journal bearing using FSI approach

In this paper, parametric analysis of various operating and surface texturing parameters on the performance characteristics of water lubricated journal bearing was carried out using Fluid Structure Interaction approach. Initially, a simulation model was validated with experimental results from the literature. An effect of journal speed and eccentricity ratio along with elastic deformation on performance characteristics viz. lubricant pressure, load carrying capacity, and coefficient of friction with different groove location was studied. Further investigation was carried out to examine the influence of the number of grooves on the performance characteristics. From the analysis, it was observed that 0–180° grooved journal bearing with 5 number of grooves has shown improved performance as compared to journal bearing with 0–90° grooved, 90–180° grooved and plain surface.

Prediction of Flow-Induced Vibrations due to Impeller Hydraulic Unbalance in Vertical Turbine Pumps Using One-Way Fluid−Structure Interaction

Vertical turbine pumps are used for critical application in power plant. Apart from power plant, these are also used in irrigation, water supply, process industries and petrochemical industries. Centrifugal and vertical turbine pumps consist of rotor geometry and a structure that can vibrate in response to excitation forces. Mass unbalances associated with mechanical and hydraulic geometry of a pump are the two major factors which create dynamic effects in terms of pump vibrations. The generated hydraulic forces resulting due to hydraulic unbalance have similar effect as of mechanical unbalance. For satisfactory operation of the pump, the vibrations in the pumps must be within acceptable limits of applicable standards. Higher level of vibrations not only leads to operational loss, but also leads to down time due to premature failure. Therefore, it is of vital importance for product designers to understand the dominating cause of unbalanced force and its source. The estimation of vibrations using numerical methods can help a designer, especially vibrations arising due to the hydro dynamic forces, for a successful design. In any centrifugal pump, including vertical turbine pump, there is always interaction between fluid and structure. Solid and fluid interaction in present case can be completed by one-way coupling method. The one-way fluid−structure interaction approach is presented in the present paper to predict the vibrations at specific operating conditions which have significant correlation with the test data. Similar philosophy has been applied for an impeller geometry which has hydraulic unbalance to predict the impact of hydraulic unbalance. The benefit of reduction in computational effort and time in this approach can be applied during the initial design stage. Two case studies of one-way FSI approach of a vertical turbine pump are discussed. The approach can be used for evaluating the impact of geometrical deviation, especially vane pitch in an impeller in terms of vibration displacements.

Prediction of flow induced vibrations in vertical turbine pumps using one-way fluid-structure interaction

Centrifugal pumps/vertical turbine pumps are important and critical equipment for operation in the power generation, water supply, process industries and petrochemical industries. All centrifugal and vertical turbine pumps have rotors and structures that can vibrate in response to excitation forces. Mechanical and hydraulic unbalance are the two major factors which can create dynamic effects in terms of pump vibrations. In many cases the resulting hydraulic forces due to hydraulic unbalance has much the same effect as the mechanical unbalance. The vibrations in the pumps must be within acceptable limits of applicable standards. If there is higher level of vibrations, it not only leads to operational inefficiencies but also causes pump failures. Hence, it is very important for designers to understand the dominating fact of unbalance force and its origin. The prediction of vibrations in a vertical turbine pump due to the hydro dynamic forces, using numerical methods can help a designer to accomplish a successful design. The interaction between solid and fluid in present case can be completed by one-way coupling method. The one-way fluid-structure interaction approach is presented in present paper to predict the vibrations at specific operating condition which has good correlation with the test data. The advantage of reduced computational effort in this approach can be utilized during initial design stage. In this paper, a case study of one-way FSI approach of a vertical turbine pump is discussed. After detailed explanation about the CFD results, one-way coupling approach is explained with comparison of vibration displacements in both numerical and test data.