Papers by Keyword: Numerical Study

Abstract: The increasing demand for electrical energy in Indonesia each year, driven by economic growth, population expansion, and the industrial sector, requires a transition from fossil energy to renewable energy (RE) to support the Net Zero Emissions (NZE) target by 2060. One such effort involves utilising the cooling water channel at the Paiton Power Plant by installing staggered co-rotating Savonius hydrokinetic turbines. In this study, a numerical simulation method was employed using ANSYS Software, with a 2-dimensional (2D) geometric model, unsteady flow, and a realisable k-ε viscous model (RKE). The TSR variations were 0, 0.2, 0.4, 0.6, 0.8, 1.0, and 1.2. Savonius turbines arranged in a staggered co-rotating configuration with varying turbine spacing (S/D) of 2.10 and 16.86, respectively. This study aim to evaluate the performance of the four staggered co-rotating Savonius turbines, presented as graphs of Coefficient of Power (CoP) and Coefficient of Moment (Cm) versus Tip Speed Ratio (TSR), velocity contours, and pressure contours. The results obtained from studying four Savonius turbines arranged in a staggered co-rotating configuration show that the greater the distance between the turbines, the better the turbine performance. At distance of S/D = 2.1, each turbine has an influence on the other. At distance of S/D = 16.86, each turbine no longer influences the others, as the performance of each turbine is similar to that of a single turbine, thereby achieving optimal turbine performance.

Abstract: This work introduces an initial finite element (FE) framework for modelling particle-substrate interaction during fluidized bed surface finishing of Laser Powder Bed Fusion (L-PBF) components. Due to the complexity of as-built surface morphology and the difficulty of experimentally observing high-speed particle impacts, the mechanisms governing material removal remain poorly understood. The proposed 3D explicit FE model simulates the impact of stainless-steel particles on representative AlSi10Mg asperities using Johnson-Cook plasticity model and damage formulations. Results show that erosion occurs mainly through localized brittle-like detachment rather than extensive plastic deformation. Sequential impacts and oblique trajectories significantly increase internal energy absorption, enhancing asperity fragmentation and the surface smoothing level. The framework provides a foundation for future optimization of Fluidized Bed Finishing (FBF) parameters for improved finishing of additively manufactured metal parts.

Abstract: This work presents a numerical study of the friction surfacing process using a GPU-accelerated Smoothed Particle Hydrodynamics (SPH) framework previously validated against experimental observations. The model is employed to examine how thermal boundary conditions, rod diameter, and rod bending angle influence material deposition efficiency and the resulting deposit geometry. Variations in rod diameter are shown to influence both the thermal response and the contact pressure, with smaller rods producing higher efficiency but exhibiting greater process fluctuations. The findings highlight the critical roles of thermal management and geometric configuration in optimizing friction surfacing performance and provide actionable insight for experimental design and process control in solid-state deposition technologies.

Abstract: To alleviate the corrosion issue, GFRP bars are usually preferred over steel reinforcing bars. However, its application causes larger deflection and brittle failure of concrete members. To solve this, steel bars can be used in combination with GFRP bars to reduce deflection and enhance ductility. Steel-GFRP hybrid reinforced concrete is a relatively recent concept, as a result, it is still in the development stage. This study numerically examines the flexure response of concrete beams reinforced with hybrid reinforcement i.e., GFRP bars combined with steel. A total of five numerical models were developed for this investigation. The analysis methodology is based on the models developed for investigation of GFRP reinforced concrete beams which was validated with experimental studies. It is found that with an increase in the replacement percentage of steel in GFRP RC beams, the ultimate load is increased. Also, it is observed that there is a significant reduction in deflection in post-cracking and pre-steel yielding region along with enhancement in the attributes of ductility which is beneficial for serviceability aspects. The steel-GFRP hybrid-reinforced concrete beams were found to have failed by yielding of steel and subsequent concrete crushing.

Abstract: This paper reports the results of a numerical study on the thermal performance of forced convection laminar flow of nanofluids flowing through a heated horizontal annular duct considering various nanoparticles types has been investigated. A numerical study is carried out for an annular duct filled with ordinary water, and three nanoparticles types of titanium dioxide (TiO₂), alumina (Al₂O₃) and copper (Cu) formed three different nanofluids. The outer cylinder is heated by a uniform and constant heat flux while the inner cylinder is thermally insulated. A numerical solution of the partial differential equations of dimensionless cylindrical coordinates associate with boundary conditions are discretized by the finite volume technique with a second-order precision and solved via a FORTRAN program. Impacts of diverse parameters of the study such as nanoparticles volume fraction from 0 to 6% of titanium dioxide, alumina, copper, and Reynolds number on the thermal and hydrodynamic characteristic are examined. The axial and average Nusselt number increases with increasing nanoparticle concentration and Reynolds number. In addition, the skin friction coefficient decreases with increasing Reynolds number. Also, no significant effect on the skin friction coefficient with the increase in nanoparticle concentration. Furthermore, the improvement was seen higher when using nanofluids made of copper (Cu).

Abstract: Numerical model of the convective-radiative heat transfer of porous media was proposed. A stainless wire-net was used as porous media. The physical properties, consisting of porosity (φ) and optical thickness (τ₀), of porous media were independent variables. The air velocity was reported in the form of Reynolds number (Re). Two equations of the conservative energy with local thermal non-equilibrium were analyzed. The gas (θ_f) and solid (θ_s) phases of conservative energy equation inside porous media were investigated. The radiative heat flux (ψ) at down-stream of solid phase emitted into outside was dealt by the P₁ approximation. From the study, it was found that the level of θ_f and θ_s decreased as Re increased because the effect of convection heat transfer. Inversely, the level of ψ increased as increasing Re. The level of θ_f, θ_s and ψ were decreased as φ increased owing to a lower volume of material depended on the increasing level of φ resulting to the heat transfer rate became lower. The level of θ_f, θ_s and ψ gave increased with τ₀ becaues a wider distance in absorping energy leading to a higher emission energy from the porous media was achieved.

Abstract: High strength steel reinforced concrete (HSRC) column refers to steel reinforced concrete column using high strength steel with its yield strength over 420MPa. So far, research on seismic behavior of HSRC columns is limited. This paper presents experimental and numerical studies on seismic behavior of HSRC columns. Two Q460 high strength steel reinforced concrete columns have been tested under low cyclic loading with constant axial compression ratio of 0.3. Flexural failure is observed in the test. From the hysteresis curves, the specimens exhibit good ductility and satisfactory energy dissipation capacity. Displacement ductility factors are larger than 2. When load descends to 85% of the peak load, the ultimate drift ratios of two specimens are 1/29 and 1/26 respectively, which meet the requirements of Chinese Seismic Design code (GB 50011). To study the seismic behavior of HSRC columns more comprehensively, a numerical model has been established for simulating the experiment using OpenSees, which adopts nonlinear beam-column element and fiber model. The numerical result fits the test data well, which validates the effectiveness of numerical model. Parametric study is then carried out to further investigate the seismic behavior of HSRC columns.

Abstract: Moderate to strong earthquakes can cause considerable damage to masonry walls which are primary structural elements for decades. In previous earthquakes, a large number of masonry walls failed due to insufficient shear strength with excessive in-plane deformation, or due to insufficient out-of- plane bending capacity of the walls in the perpendicular direction. Typically, out-of- plane failure is far more prevalent and happens earlier than in-plane failure in most past earthquakes. Thus their arises the need to strengthen this masonry walls. Generally, the compressive forces that masonry walls bear vary at different storey’s vary , therefore, walls at lower storey’s can only be applied with relatively smaller prestress due to already higher compression stresses produced by self-weight and floor dead load. Many strengthening methodsSuch as using NSM-CFRP, post tensioning, shortcreting etc. are excellent methods of strengthening masonry walls. In this the performance of post tensioned and reinforced masonry walls is analyzed. Ungrouted, partially grouted, and fully grouted Post Tensioned [PT] Masonry Walls exhibit different behavior and failure mechanisms. For this an analytical model based on an experimental study is prepared and their results are compared with ABAQUS.

Abstract: Phase change problems with natural convection in the liquid phase are of prime importance in accurate technological applications. In this work a melting of pure gallium in a rectangular cavity heated from the left wall is simulated using the finite difference method. Numerical algorithm based on dimensionless variables stream function and vorticity has been checked by experimental data of previously published papers. The effect of the grid size on results of calculations was identified. Motion of phase front and changing parameters of heat and mass-transfer were studied

Abstract: Energy and environmental problems of the economy in the world, especially in metropolitan areas caused by vehicles, is now becoming important and one of the main ways of solving this problem is using natural gas. Widespread use of gaseous fuel is heavily restricted by its storage problem in container under high pressure (20-25 MPa) in a gas state or at low temperatures (-163 ° C) in a liquid state. And the most promising solution of this problem is to develop a vessel based on of adsorption technology, which is designed for efficient storage of natural gas at moderate pressures (2-3.5 MPa).