Papers by Keyword: Fluid-Solid Interaction

Abstract: Aircraft Ditching is related primarily with the aviation safety. Firstly, the full-scaled shape of Boeing 777-200 is modeled according to the lost MH370 aircraft on 8th March. And then an Arbitrary Lagrange-Euler (ALE) fluid-field model is created for water and air domain. Next some simulation cases are implemented related to different vertical velocities using LS-DYNA nonlinear finite-element code, with the same horizontal velocity and attack angle. At the same time, the variations of the velocity of the head and tail are discussed. Consequently, Ditching overload peak occurs at the highest vertical velocity. The simulation results can deeply be applied to accident analysis of aircraft impacting on water.

Abstract: Aimed at cantilever-type foil cylinder film seal system, finite element method analysis model was established to calculate the deformation of cantilever foil under the gas pressure based on the theory of plate bending. The paper proposed a method to solve fluid-solid interaction problems in cantilever-type foil cylinder film seal system based on the numerical analysis method of cylinder gas film seal. The calculation program using the finite element method to solve fluid-solid interaction problems was developed. Calculation simulation of the film mechanical properties and steady-state performance of sealing system was realized which improved the accuracy of the sealing system performance analysis and provided the basis for the multi-parameters matching design of sealing system. The impact of adding cantilever foil support structure to the steady-state performance of sealing system and the influence of flexible support parameters on the steady-state performance of the sealing system was calculated through the method.

Abstract: Noise and vibration analysis has become thoroughly researched in vehicle engineering where is needed to keep the noise level low and affect the vehicle users. The analysis in the paper shows a frequency response study where we will determine the frequency response on a coupled structure-fluid model. The study will be made on a simplified “train wagon“ model to show in a better way the differences between a perfect coupled structure-fluid model and a non-conformal coupling. The analysis shows that the distribution of the nodes for the two cases influences the results.

Abstract: This work is concerned with the modelling of the interaction of fluid flow with flexible solid structures. The fluid flow considered is governed by the incompressible Navier-Stokes equations and modelled with stabilised low order velocity-pressure finite elements. The governing equation of fluid movement is described by an arbitrary Lagrangian-Eulerian (ALE) strategy. The structure is represented by means of an appropriate standard finite element formulation. A simple data transfer strategy based on a finite element type interpolation of the interface degrees of freedom guarantees kinematic consistency and equilibrium of the stresses along the interface. The resulting strongly coupled set of non-linear equations is solved by means of a partitioned solution procedure, which is based on the Newton-Raphson methodology and incorporates the full linearization of the overall incremental problem.

Abstract: Steel casing damage in oil wells is the primary hazards of oil production in China. There are two main reasons for the steel casing damage, one is the displacement loads on the external interface which primary come from rock creep, and another reason is temperature load on the internal surface which comes from steam injection. In this article, rock creep under fluid-solid interaction is calculated, and the displacement loads on external interface of steel casing is worked out. Then, steel casing deformation and crack propagation with temperature load is investigated. Underground rocks can be treated as porous media and rock creep is controlled by fluid-solid interaction for porous media. The method of fluid-solid interaction for finite element analysis is the calculation of two-way fluid-solid coupling for porous media; it means fully coupling between the solid and fluid solution variables. This method is analyzed and the displacement load is worked out as an example application. Finite element model is constructed; deformation and crack propagation of steel casing under multiple actions of outer loads and inner temperature load are calculated. Finally, fracture mechanism of steel casing in oil wells is analyzed, and some advice is proposed.

Abstract: An accurate three-dimensional flow passage model of the compressor has been created; the stress distribution of the main flow channel has been obtained. The aerodynamic force was applied to the impeller blades. Three kinds of loads were applied to the main blades and splitter blades. Modal characteristics of the compressor blades have been intensively studied.

Abstract: With the development of heavy oil reservoirs, it faced a series of problems. Using the theory of thermal-hydrological-mechanical (THM) coupling, a predictive model of reservoir physical properties (RPP) after thermal recovery is established. Based on this model, the changing process of reservoir physical properties is simulated by the method of numerical simulation. The obtained results show that the sand production has a significant influence on RPP. By contrast with rock deformation, it has a smaller influence on RPP. The influence caused by the former is about 5~8 times than latter. During the period of steam injection, resulting from the movement of sand grain and expansion of reservoir, both porosity and permeability of reservoir are on the rise. Due to the sand production and reservoir compression, a reducing tendency is happened in the production period. The changes of RPP in reservoir are huge along the main streamline direction, and it might change because of the presence of high-permeability path.

Abstract: This study discussed the structural analysis of blades of a small horizontal-axis wind turbine (HAWT). The computational fluid dynamics (CFD) is combined with the computational solid mechanics (CSM) into the one-way fluid-solid interaction. The aerodynamic force calculated by CFD is loaded on the structure, and the structural deformation and stress distribution are calculated using CSM. The physical model in the study is a HAWT blade with the rated power output of 500 W, and the material is engineering plastics. The Young's modulus of material is estimated according to the result of blade static load test. The accuracy of structural analysis is verified, and the blades in rated operating state are analyzed for fatigue failure. The blades in no-load running and rotor parked state are analyzed for ultimate strength. The blades of a wind turbine have large length-to-diameter ratio, and the structure approximates to a cantilever. The accuracy of linear analysis is good under a small load. However, as the load increases, the effect of geometric deformation should be considered to improve the precision of analysis. Therefore, the geometrical nonlinearity is used in this study to analyze the structure of blades in three operating states. The results showed that the safety of blades can meet the IEC 61400-2 international standard. In addition, the required safe distance between blades and tower is estimated at 157 mm according to the critical deformation analysis. According to the natural vibration modal analysis, the blades should be prevented from running at the rotating speed of 744 rpm that causes resonance for long.

Abstract: Fluid-solid coupling dynamic characteristics analysis of vertical cantilever lifting pipe in transporting coarse solid particles was conducted by adopting ADINA. Firstly, finite element models of pipe and fluid were built, which was solved by using ADINA/FSI module. Secondly dynamic characteristics of pipe vibration for different run-time, constrain conditions, volume concentration and transporting velocities were studied. Thirdly the stress and displacement characteristics were discussed under above conditions. The results were shown that stress and displacement will increase with transporting concentration and velocity rising; the shorter run-up time is, the bigger stress and displacement will be; stress and displacement of lifting pipe supportive anchor in weak constrain were greater than that in fixed connect condition. Analysis results have certain directive significance in future structure design, check, reducing vibration study for lifting pipeline in the ocean mining.

Abstract: Owing to fluid characteristics of hydraulic structure seismic response, analysis method of this problem considering fluid-solid interaction is pointed out. And seismic response of vertical plate in the water was taken as an example to show how to solve this fluid-solid interaction system and analysis the features of it. In the analysis, effects of wave frequency and water depth were considered. The results indicate that incompressible fluid model based on Arbitrary Largrange Elurian description is enough to simulate motion of fluid domain and insure computing convergence in the analysis. It also shows that peak value of structure dynamic response is larger as the consideration of fluid-solid interaction. Water depth has great effect on fluid-solid interaction and has clear nonlinear feature.