Numerical Program Research Articles

Solar Thermal Treatment: Case Study for Cashew Juice Pasteurization

Energy and food are very intertwined and important in human life. Cashew juice is a very abundant product in southern Senegal. Unfortunately, due to lack of processing and conservation, this product cannot last 24 hours without being fermented. The aim of this study is to study the heat treatment processes of agri-food products, particularly the pasteurization of cashew fruit juices. Pasteurization often uses heat from fossil fuels. In this heat treatment process of cashew juice, we are interested in the energy source. Thus thermal solar energy is used in this heat treatment. A solar thermal collector with an area of 17.9 m² and a hot water storage tank with a capacity of 0.1 m³ are used. With the pasteurization model used, the juice circulates in a copper coil immersed in hot water coming from the solar thermal field or the hot water storage tank. A numerical simulation program has been developed on Ansys Fluent 2020 R1 to study the evolution of the temperature of the juice from the inlet to the outlet of the coil. The results obtained give outlet temperatures varying from 70 to 80°C depending on the speed of circulation of the juice. We can also achieve outlet temperatures of 100°C. This means that our system can operate in sterilizer mode.

Single-sample unmixing and parametric end-member modelling of grain-size distributions with transformed probability density functions and their performance comparison using aeolian sediments

Parametric decomposition techniques including single-sample unmixing and parametric end-member modelling are routine mathematical methods used for interpreting grain-size distributions. In this study, transformed probability density functions for the Lognormal, Weibull, Skew Normal, and Skewed Generalized Normal distributions are derived and efficient open-source numerical programs applying these functions are presented. These new functions contain two free shape parameters characterizing the peak position and magnitude of a unimodal distribution, and they can be more easily initialized and constrained compared to their original counterparts, as the two shape parameters can be estimated directly from the grain-size distribution or its derivatives and can only vary within very narrow intervals. This enables the decomposition to converge to both reproducible/stable and structurally/genetically reasonable solutions. The transformed functions are applied to grain-size distributions of aeolian sediments collected from around the Tengger Desert, using both the single-sample unmixing and parametric end-member modelling methods, and the results of different functions are compared. The implications of the results for parametric decomposition of sediment grain-size distributions using unimodal mathematical distributions are discussed.

Reinforced concrete beam‐columns anchored with headed bars subjected to reversed cyclic loading: Experimental and numerical investigation

AbstractPast seismic events have shown poor performance of reinforced concrete (RC) moment resisting frames, due to failure of beam‐column joints, attributed to insufficient anchorage and poor workmanship. Inadequate development length in beam‐column joints may lead to joint strength deterioration due to detailing constraints and site errors. Alternatively, headed bars have potential to replace conventional anchorage system of development length in beam‐column joint. The paper deals with extensive experimental and numerical program conducted on RC beam‐column joints with plain and deformed (grooved and ribbed) headed bars and compared with the specimens with conventional development length. Effect of steel fibers on strength of RC beam‐column joints is also investigated. The test specimens of beam‐column joints were subjected to displacement‐controlled reversed cyclic loading and structural behavior was assessed in terms of failure mode, load carrying capacity, stiffness, drift, ductility, and energy dissipation. The strength parameters of headed bar specimens were well comparable to that of conventional specimens. Grooved‐headed and ribbed‐headed bar specimens exhibited superior load resistance as compared with plain‐headed bar specimens. Numerical analysis was carried out, whose results were in agreement with the experimental results, thus demonstrating the efficacy of headed bars as mechanical anchorage system for RC beam‐column joints.

Shape Effect of Nanoparticles on Nanofluid Flow Containing Gyrotactic Microorganisms

In this paper, we discussed the effect of nanoparticles shape on bioconvection nanofluid flow over the vertical cone in a permeable medium. The nanofluid contains water, Al2O3 nanoparticles with sphere (spherical) and lamina (non-spherical) shapes and motile microorganisms. The phenomena of heat absorption/generation, Joule heating and thermal radiation with chemical reactions have been incorporated. The similarity transformations technique is used to transform a governing system of partial differential equations into ordinary differential equations. The numerical bvp4c MATLAB program is used to find the solution of ordinary differential equations. The interesting aspects of pertinent parameters on mass transfer, energy, concentration, and density of the motile microorganisms’ profiles are computed and discussed. Our analysis depicts that the performance of sphere shape nanoparticles in the form of velocity distribution, temperature distribution, skin friction, Sherwood number and Motile density number is better than lamina (non-spherical) shapes nanoparticles.

Validation of numerical models for prediction of pressure drop in high capacity long distance lignite fly ash pneumatic conveying

This paper will validate two basic concepts of numerical models for prediction of pressure change along the transport pipeline in the case of long distance and high capacity lignite ash pneumatic conveying. Application of various friction factor correlations and variation of given parameter, led to the total of fourteen different numerical models and program codes in FORTRAN. The input data for numerical models are based on comprehensive experimental research of high capacity and long distance Kolubara lignite fly ash pneumatic conveying system within 620 MWe thermal power plant unit under operating conditions. Numerical simulation results are validated against experimental data and subjected to statistical analysis methods. The functional dependence obtained by the least squares method was evaluated using mean squared deviation and correlation ratio. The predicted pressure changes show the best agreement, with the measured decrease of pressure amplitudes along the transport pipelines, for the model based on the momentum balance of air-ash mixture flow and friction factor cor-relation given by Dogin and Lebedev for the parameter A = 1.4?10-6. This model achieved the best correlation ratio of 93.99% for Pipeline 1 and 91.33% for Pipeline 2, as well as the best mean squared deviation of 9.58% for Pipeline 1 and 13.66% for Pipeline 2. Also, the fanning friction factor values are fully consistent with previously examined cases available in the literature. Numerical simulation model can be used for prediction of the ash pneumatic conveying capacity and pressure drop for the specified transport pipeline.

Dynamic Analysis of Marine Drilling Risers Considering Steady Current, Surface Wave, Internal Solitary Wave, and Vessel Motion

In this paper, considering combined excitations of the steady current, surface wave, internal solitary wave as well as, the vessel’s surge and heave motions, a time‐domain model is established to investigate the lateral dynamic response of marine drilling risers. The finite element and Newmark‐β methods are used to solve the nonlinear partial differential equation in the time‐domain. The entire numerical solution process is realized by a self‐developed program based on MATLAB. The reliability of the numerical solution program is verified by comparing it with published numerical results. The lateral dynamic responses of a real‐scale marine drilling riser, usually used in the deep water oil/gas industry in the South China Sea, are studied. The impact level of each factor in the riser’s lateral dynamic response is discussed.

Ground Slope Stability Analysis

The article analyzes the engineering and geological conditions of the right bank, which is in a state of dynamic equilibrium, of the Oka River. Calculation schemes have been compiled to perform calculations of the total static stability of the slope for two calculated cases in the existing natural state and taking into account the water saturation of the water-bearing rocks, the boundaries of the landslide zone for various cases have been determined. The article identifies possible risks, analyzes the main models of the behavior of the soil base taking into account negative factors, calculates the stability of soil massifs using various known methods. The geometric scheme of the computational model was built on transverse profiles. The width of the calculated area was chosen in such a way that there were no changes in the stress-strain state of the array due to the introduction of artificial boundary conditions along the edges of the finite element grid. The method of calculating stability based on numerical modeling programs by reducing strength characteristics has a number of advantages over the traditionally used methods of calculating stability based on the equations of limiting equilibrium. Based on the results of calculations, the boundaries of the landslide zone for various cases were determined by the method of circular cylindrical sliding surfaces (SAM). A potential landslide zone has been identified, including residential development. Based on the calculations performed, it is proposed to provide alternative measures to ensure the safety of buildings falling into a landslide zone to ensure reliable fastening and minimal impact on the existing slope.

Distributed Interval Optimization Over Time-Varying Networks: A Numerical Programming Perspective

Distributed Interval Optimization Over Time-Varying Networks: A Numerical Programming Perspective

Efficient cost evaluation of real time applications using mathematical model in computing environment

The cloud real time services are provided in an efficient manner now a days in rapid way. The Cloud computing objective is an on-request administration model for end clients. The on-request administration model comprises memory stockpiling, equipment on the board, data handling, and different IoT applications utilizing numerical programming rationales with the upgraded fluffy model. Money saving advantage analysis is the thing that everybody should do as such as to consider a strong or a proficient framework. In any case, while thinking out on cost and advantage examination, we additionally need to figure out factors that truly influence the advantages and expenses of the framework. In creating quotes for a framework, we really want to think about some of the cost components. A few components among them are equipment, staff, office, working, and supply costs. By utilizing the fluffy model, the end clients get the best ideal cloud administrations. The proposed system provides mathematical model of rough set theory. The proposed model provides an adequate cost to the end users in terms of cloud services. For giving cloud administrations in a streamlined manner the fluffy rationale is assuming a significant part. Our proposed calculation is performing better under pressure from different calculations. The proposed algorithm finds the proposed system most suitable w.r.t cost. The reproduction of our calculation is finished in simulation system of the cloud environment.

A Reliability-Enhanced Forming Grinding Method of Cylindrical Involute Gears for Electrical Vehicles

A new form-grinding method of cylindrical involute gears for electrical vehicles (EVs) is proposed to obtain stable contact performance of gear tooth surfaces and improve their reliability based on a predesigned controllable second-order transmission error function. The predesigned second-order transmission error function is assigned to a gear drive based on design specifications of EVs. Mathematical models of modified gear tooth surfaces of the gear pair can be obtained by the predesigned second-order trans-mission error function. Moreover, a section profile of a form-grinding wheel for cylindri-cal involute gears can be determined by a coordinate transformation matrix during form-grinding and settings of computer numerical control form-grinding programs for this active design method. This approach is ultimately conducted on three cylindrical involute gear pairs to demonstrate its feasibility and effectiveness.

A Genetic Algorithm Approach to Optimal Sizing and Placement of Distributed Generation on Nigerian Radial Feeders

Mitigating power loss and voltage profile problems on radial distribution networks has been a major challenge to distribution system operators. While deployment of distributed generation, as compensators, has made a suitable solution option, optimum placement and sizing of the compensators has been a concern and it has thus been receiving great attention. Meta-heuristic algorithms have been found efficacious in this respect, yet the use of the algorithms in addressing problems of radial feeders is still comparatively low in Nigeria where analytical and numerical programming methods are common. Hence; the use of genetic algorithm to site and size distributed generator for real-time power loss reduction and voltage profile improvement on the Nigerian secondary distribution networks is presented. Backward-forward sweep load flow analysis, together with loss sensitivity factor, is deployed to identify the buses suitable for the installation of the distributed generation, while the algorithm is employed in estimating the optimum size. This approach is tested on the standard IEEE 15-bus system and validated using a Nigerian 11 kV feeder. The result obtained on the IEEE test system shows 183 kW loss using the compensator, as compared to 436 kW loss without the compensator; while on the Nigerian network the loss with the compensator was 4.99 kW, in comparison with no-compensation loss of 10.47kW. By the approach of this study, real power loss on the Nigerian feeder decreased by 52.3% together with energy cost reduction from N658,789.12 to N314,227.38. Likewise the minimum bus voltage magnitude and the voltage stability index of the network are improved to acceptable limits. This approach is therefore recommended as capable of strengthening the performance of the Nigerian radial distribution system.

Ultra-high performance recycled steel fiber reinforced concrete segments under the thrust force of TBM jacks and their environmental potentialities

Investigations have indicated that segmental tunnel linings are mainly affected during their installation phase, especially at the stage of applying thrust force. Although these concentrated thrust forces are applied temporarily, they can cause cracks and serious damage to segments. One of the main goals of this research is to evaluate the performance of ultra-high performance fiber reinforced concrete (UHPFRC) using recycled steel fibers (RSF) in tunnel lining segments. An experimental and numerical research program, including small-scaled segments (panel samples), was developed to achieve this goal. In this program, an axial load equivalent to the thrust force of a tunnel boring machine (TBM) is applied to 4 different types of samples. Three common states of defects in the support area have also been simulated to examine the more accurate and realistic performance of segment specimens. Another goal of this research is to present a hybrid design for tunnel segments using UHPFRC with RSF in order to significantly reduce the consumption of reinforcement rebar despite the significant increase in the performance of tunnel segments. Based on the results obtained, it was observed that UHPFRC segments with RSF have a good ability to reduce the opening and growth of cracks caused by the thrust forces. The new hybrid reinforced designs have shown significantly better performance compared to the conventional reinforced segments. Crack openings, the first crack starting force, and the environmental friendliness in the full-recycled fiber UHPFRC segments and two new hybrids reinforced samples were improved compared to the conventional reinforced design.

The new discontinuous Galerkin methods based numerical relativity program Nmesh

Interpreting gravitational wave observations and understanding the physics of astrophysical compact objects such as black holes or neutron stars requires accurate theoretical models. Here, we present a new numerical relativity computer program, called Nmesh, that has the design goal to become a next generation program for the simulation of challenging relativistic astrophysics problems such as binary black hole or neutron star mergers. In order to efficiently run on large supercomputers, Nmesh uses a discontinuous Galerkin method together with a domain decomposition and mesh refinement that parallelizes and scales well. In this work, we discuss the various numerical methods we use. We also present results of test problems such as the evolution of scalar waves, single black holes and neutron stars, as well as shock tubes. In addition, we introduce a new positivity limiter that allows us to stably evolve single neutron stars without an additional artificial atmosphere, or other more traditional limiters.

Immiscible two-phase model for air blasts created during natural avalanches

An immiscible two-phase model based on the incompressible Navier-Stokes (N-S) equations is used to simulate the air blast generated by an avalanche. For simplicity, the avalanche is treated as an assembly of monodisperse spherical grains and described as a continuous media. The constitutive law of local µ(I) rheology is introduced to model the moving granular material. The motion of the avalanche and the induced air blast fits into a unified framework that combines the N-S−type governing equations with a µ(I)-rheology−based kinematic viscosity and a constant viscosity. The avalanche-air interface is treated using the volume-of-fluid method. A numerical program was developed on the open-source platform OpenFOAM specifically for this model to simulate the entire evolutionary process of the avalanche as well as the air blast generated. The model was validated by comparing the results of numerical simulations with those from inclined-plane laboratory experiments. With terrain input from the Shuttle Radar Topography Mission data, the model was further applied to simulate the air blast generated in two natural avalanches, namely, the Baige and Wenjia valley avalanches fo China, which occurred in 2008 and 2018, respectively. The simulation results were found to be consistent with field observations following a statistical analysis of the properties of the air blast including flow speed and area of impact of the above-mentioned natural events.

Laboratory tests, numerical simulations and design of press-braked S690 high strength steel channel sections under major-axis combined loading

Testing and numerical modelling have been conducted to investigate the cross-sectional behaviour and resistances of press-braked S690 high strength steel channel sections under combined compression and major-axis bending. The testing programme included initial local geometric imperfection measurements and twenty major-axis eccentric compression (combined loading) tests. The numerical modelling programme included a validation study, where finite element models were developed and validated against test results, and a series of parametric studies, where the developed finite element models were adopted to generate further numerical data over a wide range of cross-section dimensions and loading combinations. The obtained test and numerical data were used to evaluate the existing design interaction curves for press-braked S690 high strength steel channel sections under combined compression and major-axis bending, as specified in the European code, North American specification, and Australian/New Zealand standard. The evaluation results revealed that the codified design interaction curves led to conservative resistance predictions, owing to the linear shapes and inaccurate end points. Improved design interaction curves featuring more efficient shapes and anchored to more accurate end points were then proposed. The proposed design interaction curves were shown to result in more accurate resistance predictions for press-braked S690 high strength steel channel sections under combined compression and major-axis bending than their codified counterparts. The reliability of the proposed design interaction curves was confirmed by means of statistical analyses.

Indoor Thermal Comfort Improvement of the Naturally Ventilated House in Tropical Climate, Indonesia

Two types of houses in North Aceh, Indonesia, are investigated in this study. Even though the hot and humid conditions throughout the year, most Indonesian stay in a house that uses natural ventilation due to energy poverty and economic conditions. Commonly, they rely on natural ventilation by opening windows to achieve thermal comfort in the indoor environment. Therefore, an on-site survey and questionnaire were performed on more than 240 occupants and 115 naturally ventilated houses to investigate thermal comfort performance between two houses based on thermal sensation vote (TSV) and thermal comfort vote (TCV). In addition, some questions related to thermal preference and body response are employed. This study also examines thermal comfort with a numerical simulations program called THERB for HAM, a coupled analysis software for heat, moisture, and air. The results show that the room comfort level was not optimal, where most occupants' feelings were warm and hot. However, type 1 is more comfortable than type 2, and simulation results confirm indoor environmental conditions. Furthermore, this study presents the adaptive behavior, where most occupants utilize the windows openings in the morning until noon and operate the fans during the night to modify indoor environment conditions to be more comfortable.

A phase-shift-periodic parallel boundary condition for low-magnetic-shear scenarios

We formulate a generalized periodic boundary condition as a limit of the standard twist-and-shift parallel boundary condition that is suitable for simulations of plasmas with low magnetic shear. This is done by applying a phase shift in the binormal direction when crossing the parallel boundary. While this phase shift can be set to zero without loss of generality in the local flux-tube limit when employing the twist-and-shift boundary condition, we show that this is not the most general case when employing periodic parallel boundaries, and may not even be the most desirable. A non-zero phase shift can be used to avoid the convective cells that plague simulations of the three-dimensional Hasegawa–Wakatani system, and is shown to have measurable effects in periodic low-magnetic-shear gyrokinetic simulations. We propose a numerical program where a sampling of periodic simulations at random pseudo-irrational flux surfaces are used to determine physical observables in a statistical sense. This approach can serve as an alternative to applying the twist-and-shift boundary condition to low-magnetic-shear scenarios, which, while more straightforward, can be computationally demanding.

Inclusive production cross sections at N3LO

We present for the first time the inclusive cross section for associated Higgs boson production with a massive gauge boson at next-to-next-to-next-to-leading order in QCD. Furthermore, we introduce n3loxs, a public, numerical program for the evaluation of inclusive cross sections at the third order in the strong coupling constant. Our tool allows to derive predictions for charged- and neutral-current Drell-Yan production, gluon- and bottom-quark-fusion Higgs boson production and Higgs boson associated production with a heavy gauge boson. We discuss perturbative and parton distribution function (PDF) uncertainties of the aforementioned processes. We perform a comparison of global PDF sets for a variety of process including associated Higgs boson production and observe 1σ deviations among predictions for several processes.

Press-braked ferritic stainless steel slender channel section beam–columns: Tests, simulations and design

This paper reports an experimental and numerical investigation into the buckling behaviour and resistance of press-braked ferritic stainless steel slender channel section beam–columns under combined compression and minor-axis bending moment. An experimental programme was firstly performed, including material coupon tests, initial global and local geometric imperfection measurements and ten beam–column tests. The experimental programme was followed by a numerical modelling programme, where finite element models were developed and validated against the experimental results and then adopted to conduct parametric studies to generate additional numerical data. Based on the obtained test and numerical data, the existing design interaction curves, as set out in the European code, American specification and Australian/New Zealand standard, were evaluated and found to result in conservative and scattered resistance predictions. An improved design interaction curve, anchored to more accurate end points and featuring more appropriate shape, was then developed and shown to offer more accurate and consistent resistance predictions for press-braked ferritic stainless steel slender channel section beam–columns over the codified design interaction curves. Statistical analyses were also performed to confirm the reliability of the new proposal.

Numerical simulations of combined size effects acting on an open-hole laminated composite plate under tension

Numerical and experimental research programs have been carried out to investigate the effect of scaling on the tensile strength of notched composites. This paper presents a computational study of scaled open-hole tensile tests using the Discrete Ply Model (DPM) method. This finite element model is discrete, and only a small number of parameters are required from experimental characterization tests. Experimental and numerical strength values are compared here, and reveal that DPM simulations tend to slightly overestimate strength values, with an average discrepancy of 9.7%. However, DPM Results show that such modeling simulates both the reduction in strength when specimen size is increased for sublaminate level scaled specimens, where failure is fiber dominated, and the increase in strength when specimen size is increased for ply level scaled specimens, where failure is delamination dominated. In all cases, increasing the total thickness of the specimen leads to a decrease in strength and this effect is dominant over the effect of increasing hole diameter. As well as the variation in strength, three distinct failure mechanisms are observed: fiber failure with extensive matrix damage (pull-out failure), fiber failure with little or no matrix damage (brittle failure) and delamination failure. Comparisons with experiments demonstrate that tensile strengths, damage propagation scenarios and failure patterns are predicted with acceptable accuracy.