Numerical modeling on dynamics of droplet in aircraft wing structure at different velocities

Purpose The purpose of this paper is to find the droplets impact on the airplane wing structure. Two kinds of characteristics of the droplet at different velocity and viscosity are assumed. The droplet is assumed to be spherical cubic form and it is injected from the convergent divergent nozzle with a passive control. Design/methodology/approach This paper presents the results of a numerical simulation of droplet impact on the horizontal surface. The effects of impact parameters are studied. The splash effect of the droplet also visualized. The results are presented in form of stress, strain, displacement magnitude of the droplet. Findings Crosswire is used as passive control. The behavior of the droplet impact is observed based on the kinetic energy and the gravitational forces. Originality/value The results predict that smooth particle hydrodynamic designed droplet not only depend on the equation of state of the droplet but also the injection velocity from the nozzle. It also determined that droplet velocity is depending on the viscosity of the fluid.

Dynamic response of RC sheds against the impact of rock block with different shapes and angles

This study aimed to quantitatively identify the influence of the block impact angle and block shape on the impact effect of reinforced concrete RC sheds. The smooth particle hydrodynamic (SPH) method and finite element method (FEM) were coupled and used to solve the simulation difficulty of large deformation of the sand buffer layer. The accuracy of the coupled model was verified by the full-scale test data. Finally, the impact forces and the dynamic responses of the RC shed were analysed, focusing on the effects of the block impact angle and shape. The numerical results show that the coupled SPH-FEM method is effective for simulating how block impacts the RC shed. The block impact angle and shape can significantly influence the normal and tangential impact forces. The design of the RC shed based on the assumption of blocks as free-falling spherical projectiles can lead to inaccuracy in some impact scenarios.

Using the Goldilocks Principle to model coral ecosystem engineering

The occurrence and proliferation of reef-forming corals is of vast importance in terms of the biodiversity they support and the ecosystem services they provide. The complex three-dimensional structures engineered by corals are comprised of both live and dead coral, and the function, growth and stability of these systems will depend on the ratio of both. To model how the ratio of live : dead coral may change, the ‘Goldilocks Principle’ can be used, where organisms will only flourish if conditions are ‘just right’. With data from particle imaging velocimetry and numerical smooth particle hydrodynamic modelling with two simple rules, we demonstrate how this principle can be applied to a model reef system, and how corals are effectively optimizing their own local flow requirements through habitat engineering. Building on advances here, these approaches can be used in conjunction with numerical modelling to investigate the growth and mortality of biodiversity supporting framework in present-day and future coral reef structures.

Erosion Evaluation of Gas-Turbine Grade CMC’s at Room and Elevated Temperatures

The objective of this study is to predict ceramic matrix composites (CMCs) erosion behavior and Retained Strength (RS) under environmental conditions using an Integrated Computational Material Engineering (ICME) physics-based approach. The state-of-the-art erosion analysis using phenomenological algorithms and Finite Element Models (FEM) models follows a test duplication methodology and is not able to capture the physics of erosion. In this effort, two CMC systems are chosen for Erosion evaluation: (a) Oxide/Oxide N720/alumina; and (b) MI SiC/SiC. Experiments are conducted at room and elevated temperatures (RT/ ET). Erosion testing considers: (i) a high velocity oxygen fuel (HVOF) burner rig for ET, and (ii) a pressurized helium impact gun for RT. Erodent particles are chosen as alumina and garnet. Experimental observations show that the type of erodent materials affects CMC erosion degradation at ET. Alumina exhibits to be an effective erodent for maintaining a solid phase particle erosion, while Garnet, experiences some degree of melting. Erosion of the oxide/oxide composite is more severe for the same erodent, temperature, mass, and velocity conditions than the MI SiC/SiC composite for all conditions tested. In general, increasing erosion temperature results in increasing erosion rate for the same erodent mass/velocity condition. In conjunction with experiments, a computational Multi-Scale Progressive Failure Analysis (MS-PFA) is also used to predict erosion of the above-mentioned material systems at RT/ET. The MS-PFA augments FEM by a de-homogenized material modeling that includes micro-crack density, fiber/matrix, interphase, and degrades both fiber and matrix simultaneously during the erosion process. Erodent particles are modeled by Smooth Particle Hydrodynamic (SPH) elements. Erosion evolution in CMCs considering strain rate effect predicts a) spallation, b) mass-loss, and c) damages in fiber, matrix, and their interphase. ICME modeling is capable of predicting the erosion process and reproducing the test observation for the MI SiC/SiC at RT, where: a) erodent particles break up the layer of matrix covering fiber due to interlaminar shear (delamination); b) fiber is fractured because of brittle behavior; c) the process (erosion tunneling) continues till it gets to the next thick matrix layer that slows down the tunneling; and d) Erosion tunnel widens as exposed fiber layers are removed (eroded). Simulations are also performed for erosion of the oxide/oxide due to glass beads at RT and ET. Predictions show that erosion rate is lower at ET because voids in the CMC vanish and the glass beads are less effective at ET. Finally, prediction of retained strength of eroded CMC test specimens is predicted by MS-PFA.

Smooth Particle Hydrodynamic and URAN Visualization of Multiphase Flow

Significant research is being conducted in the simulation of fluid flows due to the increase in employing the physics of the fluid flow to either commercial, in-house or open source codes. The analysis of the fluid flow is mainly based on the Lagrangian or the Eulerian approach. Many of the simulation codes employ the Eulerian approach due to its simplicity. These codes are based on several numerical techniques and yet few benchmarks have been conducted. However, the codes which employ the Lagrangian approach seem to be promising and may accurately simulate fluid flow phenomena. In this paper, a comparative analysis of the Lagrangian and Eulerian approach is investigated for a water droplet in a tank. The velocity field and the total pressure of the fluid are generated for the simulation by employing Ansys Fluent for the Eulerian approach and DualPhysics for the Lagrangian approach. The fluid structure and the fluid flow development are compared in order to assess the capability of each approaches in analysing the investigated fluid flow. This study may play a significant role on the importance of employing the Lagrangian approach for fluid flows where complex fluid structure occurs.

Suite for Smooth Particle Hydrodynamic Code Relevant to Spherical Plasma Liner Formation and Implosion

Three-dimensional (3D) modeling of magneto-inertial fusion (MIF) is at a nascent stage of development. A suite of test cases relevant to plasma liner formation and implosion is presented to present the community with some exact solutions for verification of hydrocodes pertaining to MIF confinement concepts. MIF is of particular interest to fusion research, as it may lead to the development of smaller and more economical reactor designs for power and propulsion. The authors present simulated test cases using a new smoothed particle hydrodynamic (SPH) code called SPFMax. These test cases consist of a total of six problems with analytical solutions that incorporate the physics of radiation cooling, heat transfer, oblique-shock capturing, angular-momentum conservation, and viscosity effects. These physics are pertinent to plasma liner formation and implosion by merging of a spherical array of plasma jets as a candidate standoff driver for MIF. An L2 norm analysis was conducted for each test case. Each test case was found to converge to the analytical solution with increasing resolution, and the convergence rate was on the order of what has been reported by other SPH studies.

TSUNAMI GENERATION BY EARTHQUAKES: SEABED TOPOGRAPHY AND INERTIAL EFFECTS

In this presentation, we examine the effects of the shape and height of a moving bed on the generated surface gravity waves using the 3-D Smooth Particle Hydrodynamic model, GPUSPH (Hérault et al., 2010). Further, we investigate the relative importance of the inertial effects on the general characteristics of the generated Tsunami in the near- and far-field for various rates of the bed displacement, ranging from creeping to impulsive regimes. The sensitivity of the inertial effects on the shape of the moving bed is also discussed. Finally, the characteristics of the acoustic waves generated during the various bed displacement scenarios are examined.

VORTEX FORCE ANALYSIS OF WAVE-DRIVEN NEARSHORE CIRCULATION

In this presentation, we examine 3-D structure of nearshore circulation driven by short-crested wave breaking using the 3-D Smooth Particle Hydrodynamic model, GPUSPH (Hérault et al., 2010). The alongshore variation of incident wave field has been imposed by using the method of intersecting wave trains proposed by Dalrymple (1975). We use the 3-D vortex force formalism to analyze the various forcing mechanisms of the observed circulation. Of particular interest is the relative importance of the vortex force compared with the other wave-averaged forces. The accuracy of the depth-averaged vortex force based on the formulation of Smith [2006] is also examined.

A smooth particle hydrodynamic model for two-dimensional numerical simulation of Ti–6Al–4V serrated chip deformation based on TANH constitutive law

The saw-tooth chip formation is one of the main machining characteristics in cutting of titanium alloys. The numerical simulation of saw-tooth chip formation, however, is still not accurate, since most of these numerical simulation models are based on traditional finite element method, which have difficulties in handling extremely large deformation that always occurs in the cutting process. Furthermore, these models adopt the Johnson–Cook damage constitutive law that is implemented in commercial codes such as ABAQUS® and LS-DYNA® to describe the dynamic mechanical properties of material, but Johnson–Cook damage constitutive law cannot account for the material of behavior due to strain softening and the dynamic recrystallization mechanism that occurs in the cutting process of Ti–6Al–4. Therefore, this work introduces a material constitutive model named hyperbolic tangent (TANH) and an improved smooth particle hydrodynamics method, and then develops an improved cutting model for Ti–6Al–4V titanium alloy through our in-house code to predict saw-tooth chip morphology and cutting forces. When compared to the experiments and Johnson–Cook damage model, the improved cutting model better explains and predicts the shear localized saw-tooth chip deformation as well as cutting forces.