Numerical Analysis Method Research Articles

SOFTWARE IMPLEMENTATION OF THE METHOD OF CALCULATING THE ENERGY CONSUMPTION OF A BUILDING

In the conditions of a constant increase in energy prices, the desire to reduce harmful emissions to the atmosphere, as well as the shortage of fossil fuels that can be used for heating, methods of increasing energy efficiency and energy saving attract attention. One of the main characteristics of a building's energy efficiency is its energy consumption - a value that determines the amount of energy that must be spent on heating or conditioning the interior of the building to ensure a comfortable temperature. This work is devoted to the development of the calculation method and its software implementation. In the course of the study, several of the most common methods of heat transfer analysis were developed, in particular, methods of numerical analysis based on the approximation of differential equations and engineering calculation methods using equations describing various mechanisms of heat transfer. Having determined that none of the methods is optimal for solving the set goal, it was decided to synthesize a new method, using the best approaches from all the processed information. The result was the developed method, the basis of which were the formulas for calculating thermal conductivity, convection, thermal radiation, and heat capacity, which in terms of the structure of its implementation is similar to numerical methods, where the calculation progresses gradually along two coordinates: spatial and temporal, and also, in some formulas, there are weights coefficients similar to those used in the finite element method. The calculation is organized in such a way that a more detailed analysis of the building's thermal behavior is also possible. The availability of such a method, as well as the computer system in which it is implemented, will allow to quickly obtain fairly accurate values of the building's energy needs. The characteristics of the computer system make it convenient for use in the design of private and multi-apartment buildings with clear energy efficiency requirements ,

Incorporating Life Cycle Assessment in the Green Metric Ranking: a Conceptual Approach

Integrating sustainability principles into their daily operations is an overarching goal of universities and higher education institutions (HEIs), as knowledge multipliers, have to perform (Filimonau et al., 2021).Various studies have demonstrated that the operational activities of universities cause GWP emissions and, in general, negative environmental impacts, due mainly to student and staff mobility, on-campus energy and water consumption, and waste production (Jürgens et al., 2023). Findler et al. (2019) outlined numerous analytical methods, ranging from input-output analysis to full Life Cycle Assessment (LCA), for evaluating the carbon footprints of universities and colleges.Concurrently, a variety of tools have been devised to measure sustainability based on environmental metrics, such as the Green Metric (GM) ranking developed by Universitas Indonesia (UI). The GM, which is first in which tops university sustainability rankings (Marrone et al., 2018), rates HEIs by utilizing 51 criteria across 6 rating areas. Researchers analyzed the UI Green Metric World Ranking system to examine the requirements for a fair sustainability ranking of worldwide HEIs, although the latter were only examined in general without inspecting each item separately (Boiocchi et al., 2023).In order to lessen the environmental impacts of HEIs, recognized and robust methods must be used to identify appropriate and effective measures. LCA is a standardized (ISO 14040 and 14044) tool for quantifying and reducing environmental impacts throughout the entire life cycle of a product, service, or organization.This study is focused on understanding how LCA can be integrated into GM, and more specifically, how it can assist in achieving a consistent and structured review of specific indexes such as EC4, EC7, EC8, WR2, and TR1.The analysis was conducted by comparing the items one by one. Such a method was implemented as a results of the authors' specialized background, the scientific literature of interest, and the adoption of a critical thinking approach.The study results emphasize the necessity of incorporating LCA into the environmental sustainability strategies of HEIs. This integration is crucial for developing a robust approach adaptable to various local contexts, enhancing the precision in assessing and improving HEIs' sustainability practices. Such a strategy will align HEIs' operational activities more effectively with sustainable development goals. The application of the conceptual approach to a case study is recommended.

SIMULASI PENGENDALIAN PERSEDIAAN ALAT TULIS KANTOR PADA DINAS PERKEBUNAN DAN PETERNAKAN PROVINSI SUMATERA UTARA DENGAN METODE MONTE CARLO

In a Government Agency, office stationery supplies are an absolute necessity. The provision of adequate office stationery will facilitate performance. This study aims to predict the demand for office stationery using Monte Carlo Simulation. Monte Carlo is a numerical analysis method that uses random number samples. The data used in this study are primary data in the form of the number of stock items and the number of requests for goods from January to December 2023. The accuracy result using the Monte Carlo method for Year 2024 is 91.78%. This shows that the Monte Carlo method simulation can be used to predict the demand for stationery for the following year.

DualFluidNet: An attention-based dual-pipeline network for fluid simulation

Fluid motion can be considered as a point cloud transformation when using the SPH method. Compared to traditional numerical analysis methods, using machine learning techniques to learn physics simulations can achieve near-accurate results, while significantly increasing efficiency. In this paper, we propose an innovative approach for 3D fluid simulations utilizing an Attention-based Dual-pipeline Network, which employs a dual-pipeline architecture, seamlessly integrated with an Attention-based Feature Fusion Module. Unlike previous methods, which often make difficult trade-offs between global fluid control and physical law constraints, we find a way to achieve a better balance between these two crucial aspects with a well-designed dual-pipeline approach. Additionally, we design a Type-aware Input Module to adaptively recognize particles of different types and perform feature fusion afterward, such that fluid-solid coupling issues can be better dealt with. Furthermore, we propose a new dataset, Tank3D, to further explore the network’s ability to handle more complicated scenes. The experiments demonstrate that our approach not only attains a quantitative enhancement in various metrics, surpassing the state-of-the-art methods, but also signifies a qualitative leap in neural network-based simulation by faithfully adhering to the physical laws. Code and video demonstrations are available at https://github.com/chenyu-xjtu/DualFluidNet.

On reliability and quality of functioning of power grids (as exemplified by the branch of PJSC Rossetti Volga – Samara Distribution Networks)

The analysis of the electric energy transmission through the distribution electric networks of the branch of PJSC Rosseti Volga — Samara Distribution Networks over the period of 2018 – 2022 was carried out. The structure of the company is considered, the characteristics of the main elements of the power grids under study are given, the balance of the electric energy transmission in and out of the company's networks is estimated. Based on the information published in public media on the accident rate in the company's power grids, assessment was made of the number of emergency situations that occurred over the period under study, assessment of the duration of interruptions in power supply to consumers, as well as the amount of undersupplied electric energy caused by these interruptions. The influence of the seasonal component on the number of emergencies during the period under study is considered. Based on the 2022 data, the analysis of the main causes of damage to components of power grids and the classification of failures are presented, their main characteristics over the period in question are considered. The percentage ratio of the number of failures for the most characteristic reasons to the total number of shutdowns over the period under study was established, and the classification of the number of emergency shutdowns according to the degree of undersupply of electrical energy was made. General scientific methods, numerical methods of analysis, methods of the electrical circuit theory were used in the study. To visualize the results of the analysis, the technologies of the MATLAB graphics editor were used. The results obtained may be of interest to the heads of power grid companies, as well as researchers and engineers engaged in research in the field of power supply reliability.

PHREEQ C Modelling Tool Application to Determine the Effect of Anions on Speciation of Selected Metals in Water Systems within Kajiado North Constituency in Kenya

Heavy metals and anions in water pose a significant risk to living organisms, including humans, and must therefore be carefully monitored. There are numerous approaches and methods of analysis to choose from. Using the PHREEQ C chemical modeling technique, this study looked at the effect of certain anions on the speciation of selected metals in the water environment of Kajiado North. Twenty-five sampling points were used in the study, which covered five Kajiado North election wards. Samples were taken twice during the dry and rainy seasons, in November 2019 and March 2020. Using standard methods, physicochemical characteristics were analyzed, concentrations of selected heavy metals using the (ICP- OES) 7000 series, and selected anions using a multi parameter photometer, their concentration values compared to the specified maximum contaminant level and speciation analysis done using the Computer-based technique PHREEQ C. The range observed for pH, temperature, electrical conductivity, sulphate, chloride, fluoride, nitrate and carbonates was 7.43- 9.30, 23.0 -28.0oC, 335-1265μS/cm, 4.54-361.41mgL-1, 5.19-184.6 mgL-1, 0.01-2.90 mgL-1, 0.1-8.6 mgL-1, and 3.18-55.19 mgL-1 respectively. The range observed for heavy metals was 0.06-1.08 mgL-1 , 0.00 -0.05082 mgL-1, 0.01-0.02597 mgL-1, 0.01-0.01610 mgL-1, 0.00 -0.0327 mgL-1, 0.00-42.7842 mgL-1, and below detection limit, for Fe, Mn, Cu, Zn, Pb, Mg, and Cd respectively. The findings revealed that Cd, Zn, Cu, Cl-, NO2-, and eElectrical cconductivity concentrations were below the WHO levels. At certain sampling points, however, SO42-, F-, Pb, Fe, and Mn were above WHO limits. In some water systems, traces of SO42-, F-, Cu, Fe, Cd, and Mn were found to pose significant health risks, according to PHREEQ C speciation analysis. Anion concentrations, pH, temperature, and metal concentrations are all important variables in modeling. Metals formed anion complexes and the total abundance of metal species was classified at the highest levels as Fe(OH)3, PbCO3, Zn(CO3)2, Cu(CO3)2, Mn+2, MgF-, and Mg+2. At a water system temperature of 25oC without anions, it was found to have the highest chemical species. CuCO3, CuNO3, and CuOH+ complexes are also formed at low pH. Based on the data for different metal species at different pH values, the bioavailability of metal species definitely depends on pH.

Simultaneous analysis of continuously embedded Reissner–Mindlin shells in 3D bulk domains

AbstractA mechanical model and numerical method for the simultaneous analysis of Reissner–Mindlin shells with geometries implied by a continuous set of level sets (isosurfaces) over some three‐dimensional bulk domain is presented. A three‐dimensional mesh in the bulk domain is used in a tailored FEM formulation where the elements are by no means conforming to the level sets representing the shape of the individual shells. However, the shell geometries are bounded by the intersection curves of the level sets with the boundary of the bulk domain so that the boundaries are meshed conformingly. This results in a method which was coined Bulk Trace FEM before. The simultaneously considered, continuously embedded shells may be useful in the structural design process or for the continuous reinforcement of bulk domains. Numerical results confirm higher‐order convergence rates.

Thermal modal analysis of hypersonic composite wing on transient aerodynamic heating

Considering the influence of thermal stress and material property variations, this study employs the Navier–Stokes equations and Fourier heat conduction law to establish a semi-implicit time-domain numerical analysis method for hypersonic aerothermal-structural coupling. Study the temporal variation pattern of different regions of the composite material wing under aerodynamic heating. Using the obtained transient temperature field of the wing, the thermal modal of the wing at different time points is calculated using the finite element method. Additionally, it conducts an analysis and discussion on the factors influencing the thermal modal. Composites can be effectively utilized as thermal protection materials for aircraft. During the aerodynamic heating process, the leading edge temperature reaches thermal equilibrium first, followed by the trailing edge, and the belly plate experiences a slower thermal response. Temperature rise significantly affects higher-order modes, with the change in material properties during the early stages of heating being the dominant factor. This leads to a faster decrease in natural frequency. As heat conduction progresses, the influencing factors of thermal stresses gradually increase, and the natural frequency decreases slowly or even rises.

High-fidelity flexible multibody model considering torsional deformation for nonequatorial space elevator

Space elevators are a promising technology for future space transportation. The primary component of a space elevator is a tether deployed from a geostationary orbit towards the Earth and into deep space. Payloads can be transported using a climber moving along the tether. However, obtaining a deeper comprehension of the precise dynamics of a space elevator is challenging. The tether could have various deformations such as elongation, bending, and torsion owing to its flexible nature and the low level of vibration damping in space. Therefore, understanding those effects on the tether is essential for the design concept of a space elevator. Reproducing the behavior of space tether systems on the ground is challenging, which is primarily due to the scale of the system and the difficulty of accurately replicating a space environment. Thus, high-fidelity numerical analysis methods are required to analyze the dynamic response of space elevators precisely. Previously proposed analysis models of space tether systems with climbers have focused on elongation, bending, and rigid body motion of the tether, and the effect of torsional deformation has been neglected. However, a tether can be twisted easily owing to its low torsional stiffness. This study established high-fidelity numerical simulation models for space elevators considering large deformations including the torsion of a tether. This study developed a flexible multibody model with a moving climber using the absolute nodal coordinate formulation with 14 degrees of freedom. Further, the gravitational perturbation caused by the non-sphericity of the Earth was considered. Using the constructed model, the motion and deformation of nonequatorial space elevators caused by the climber motion and the disturbance in the space environment were investigated. The obtained results indicate that gravitational perturbation can induce torsional deformation, particularly at higher anchor latitudes.

Digital implementation method and research on thermal life loss of power transformers

AbstractThe report of the 20th National Congress of the Communist Party of China pointed out that it is necessary to accelerate the construction of digital China, and actively develop equipment intelligence, digitalization, and high‐end equipment manufacturing. With the construction of a new round of digital China, the safety of digital technology and high‐end equipment is particularly important for power grid. Transformer is an important link of power grid operation. The destructive thermal failure of transformer has become a hot research issue in the power industry. At the same time, there are more and more power electronic equipment in the power grid, which makes the regulation and control more and more complicated. Taking a 1000 kVA oil‐immersed transformer as an example, the magnetic, current, and thermal multi field coupling numerical analysis method is first used to simulate and analyse the operation status of the transformer. By comparing the simulation results with the monitoring data results, the error of the results is controlled within 5%. Finally, the multi‐state characteristic parameters of the transformer are monitored through sensors, and the numerical simulation analysis results are integrated with the state monitoring results to build a transformer thermal life loss assessment system. The method in this paper can evaluate and analyse the running state of transformer in real time, which is of great significance for the power company to formulate the treatment measures.

Damage evolution of tunnel lining under creep action considering interlayer effect in gently inclined layered surrounding rock

The anisotropy and creep characteristics of layered sandstone mudstone with different structural inclinations have a significant impact on the safety of tunnel construction and operation. we conducted research of the layered sand-mudstone of the Yunding Tunnel on the Dazhou-Chengdu line, based on the mechanical response mechanism of layered surrounding rock and employing a numerical coupling analysis method, established a creep damage mechanical model of layered rock to study the progressive failure characteristics of layered rock and the failure mechanism of tunnel lining. The results indicate that:(1) The response mechanism of layered rock mechanics based on the delamination effect can well reflect the progressive fracture of the layered rock and distinguish the failure mode of layered rock; (2) The established layered rock mechanics contact model can effectively characterize the anisotropic macroscopic mechanical properties of layered sand-mudstone in biaxial test and triaxial creep test; (3) The fracture characteristics of the layered surrounding rock matrix change significantly with the change of the dip angle of the structural plane, the cracks mainly appear in the direction perpendicular to the structural plane. And it can be determined that the critical angle of sliding failure of layered sand mudstone is α1 = 28.77°, α2 = 65.47° (4) The damage evolution of lining can be divided into four states: 1. elastic state 2. injury working state 3. ultimate bearing state 4. damage state. With the increase of the dip angle of the structural plane, the time for the lining to enter the ultimate bearing state is gradually delayed, and the delayed rate shows the characteristics of ’slower-faster-slower’. This research achievement can provide a certain foundation for the analysis of the failure mode and the failure mechanism of tunnel lining.

Advancements in numerical modeling of ideal multicomponent isotope separation Cascades: A comparative study

The complexity of operational conditions in stable isotope separation cascades necessitates the utilization of numerical methods for cascade design and performance analysis. This study focuses on solving a system of nonlinear algebraic equations derived from the mass and energy balance equations, which is a fundamental challenge in analyzing and designing cascades and developing numerical methods. Two existing numerical algorithms were selected from the literature and modified for quasi-ideal cascade systems. The performance of these algorithms was examined and compared, with a particular emphasis on influential parameters such as the number of stages, the number of isotopes, and the separation factor. The first algorithm solves the concentration and flow equations separately, while the second algorithm solves all equations simultaneously. The results indicate that the first algorithm exhibits significant superiority over the second algorithm. In most cases, the second algorithm either fails to converge or exhibits a slower convergence speed. Additionally, the results demonstrate that increasing the number of stages impacts the convergence time, while an increase in the separation factor leads to greater convergence complexity.

Parsnp 2.0: scalable core-genome alignment for massive microbial datasets.

Since 2016, the number of microbial species with available reference genomes in NCBI has more than tripled. Multiple genome alignment, the process of identifying nucleotides across multiple genomes which share a common ancestor, is used as the input to numerous downstream comparative analysis methods. Parsnp is one of the few multiple genome alignment methods able to scale to the current era of genomic data; however, there has been no major release since its initial release in 2014. To address this gap, we developed Parsnp v2, which significantly improves on its original release. Parsnp v2 provides users with more control over executions of the program, allowing Parsnp to be better tailored for different use-cases. We introduce a partitioning option to Parsnp, which allows the input to be broken up into multiple parallel alignment processes which are then combined into a final alignment. The partitioning option can reduce memory usage by over 4× and reduce runtime by over 2×, all while maintaining a precise core-genome alignment. The partitioning workflow is also less susceptible to complications caused by assembly artifacts and minor variation, as alignment anchors only need to be conserved within their partition and not across the entire input set. We highlight the performance on datasets involving thousands of bacterial and viral genomes. Parsnp v2 is available at https://github.com/marbl/parsnp.

Experimental Study on Spray Uniformity

This study involves simulating rainfall conditions to analyze rainfall intensity and spray uniformity, conducting environmental experimental research. Using numerical analysis methods, water mass fraction cloud maps under different flow conditions were obtained to determine the relationship between uniformity, water flow rate, and water mass fraction. Based on the simulation results in accordance with relevant standards, two methods for measuring rainfall uniformity are selected based on water pressure, nozzle type, and spray height as basic parameters for setting measurement points, and rainfall environmental simulation experiments are conducted. The theoretical analysis provides a clearer representation of water quality distribution than steady-state analysis; water mass fraction is proportional to water flow rate, while uniformity is independent of water flow rate. Through comprehensive comparison of uniformity data for different nozzle models under varying water pressure and height conditions, recommendations are made for the placement of rain gauges in rainfall environmental experiments. Adjusting various test environment parameters can provide references for the test lab to accurately select test equipment, parameter measurement, and evaluation; the water mist environment generated during rainfall is simulated through spray towers, and the numerical uniformity test results of the water mist environment are consistent with the requirements, providing theoretical data support for developing more authoritative test methods for equipment sprinkler tests and ultra-fine water mist environment simulation in the future.

Research on the Overall Influence of Magnus Cylinders on Airfoil Structures and Structural Optimization

With the coupling effect of Magnus cylinder and symmetric airfoil as the research object, the numerical analysis method is used to study the influence of Magnus cylinder layout position and protruding height ratio on the aerodynamic characteristics of the airfoil. Based on the aerodynamic law of Magnus airfoil and Optistruct deformer optimisation method, the optimisation model of Magnus airfoil structure is proposed. Results reveal that the placement of the Magnus cylinder near the leading edge of the upper surface and the trailing edge of the lower surface significantly impacts the aerodynamic characteristics of the Magnus airfoil. Moreover, as the protruding height ratio increases, the aerodynamic performance of the airfoil experiences an initial enhancement followed by a reduction. Under the conditions of an 8° angle of attack and a Reynolds number of 9.5×105, the optimized aerodynamic performance of the Magnus airfoil demonstrates a remarkable increase of 17.5% compared to the baseline airfoil, accompanied by a significant reduction of 28.1% in stress concentration.

Research on Mathematical Modeling of Critical Impact Force and Rollover Velocity of Coach Tripped Rollover Based on Numerical Analysis Method

Research on Mathematical Modeling of Critical Impact Force and Rollover Velocity of Coach Tripped Rollover Based on Numerical Analysis Method

Launch Dynamics Analysis of Amphibious Launch Vehicle on the Sea

Due to its agility, concealment and excellent amphibious combat capability, amphibious vehicles can perform tasks in complex terrain and environment, and have important application value in the field of national defense and people ’s livelihood. In this paper, the method of experimental data-driven numerical simulation analysis is used, combined with batch simulation technology, and the frequency histogram in probability statistics is used to study the launch safety of amphibious vehicles under random waves, and the influence of missile launch sequence and launch time interval on missile launch is explored. The results show that the driving and sea launch of the amphibious vehicle are safe under the experimental conditions. The partial attitude angle of the car body and the attitude angle of the missile roughly conform to the normal distribution; considering the relationship between the weight of the vehicle body and the ejection load impulse, the launch sequence and the launch time interval will not have a great impact on the missile launch. By evaluating the driving safety of the amphibious vehicle and the launch safety of the missile, this paper can provide some theoretical significance and engineering application value for the sea launch of the amphibious vehicle.

State inference for low-observable distribution system based on graph convolutional network

Distribution network state inference refers to the process of calculating the state variables of each node by using measurement data and network models in the operation of the distribution system. However, the uneven measurement layout and insufficient measurement accuracy in the distribution network have brought great challenges to the state inference of the distribution network. This paper proposes a low-observable distribution network state inference method based on a graph convolution network (GCN), which uses sparse measurement data to infer missing measurement information. Firstly, the observability of the distribution network is analyzed by the numerical probability analysis method. Secondly, the GCN is employed to extract feature information from measurement data and integrate these features. The state inference model of the distribution network based on the GCN is established. Subsequently, power flow constraints of the distribution network are incorporated into the GCN training process to enhance the precision of the generated data. Ultimately, the efficacy of the proposed method is validated using the IEEE 33-node distribution system.

Numerical Study on Cable Force Adjustment System for Replacing Slings of In-Service Suspension Bridges

To conduct a systematic investigation on the replacement scheme for slings in service of suspension bridges, five feasible tensioning schemes were determined based on numerical simulation and analytical methods using the sling replacement project of an existing bridge as a case study. The safety performance of the bridge was evaluated by considering parameters such as sling position, quantity, order, and force value. According to the coupling relationship between different slings during the tensioning process, a precise analytical calculation model for adjusting cable force of the suspender is determined. The findings demonstrate that the dynamic performance of the completed bridge solely depends on its final state and remains unaffected by the intermediate tensioning process of suspension. The research findings suggest that symmetrically batch or stepwise tensioning can be applied to the suspension bridge slings with cable adjustment sequence from both ends to middle span replacement scheme to minimize structural response and optimize mechanical properties.

Analytical method for calculating internal forces and deformations in foundation pit support under asymmetric loading

Sheet pile walls are significant forms of foundation pit supports that are widely employed in foundation pit support projects in combination with inner bracing. The complex geological conditions, surrounding environments, and earthwork excavations associated with foundation pits generally lead to noticeable asymmetric loading on a support system, posing challenges for accurately calculating the internal forces and deformations. To study the calculation methods for the internal forces and deformations in foundation pit support structures and bracing systems under asymmetric loading, a new model was established for foundation pits subjected to asymmetric unbalanced force loading on opposite sides. This method provides an adjusting technique for bracing forces on both sides based on the principle of equalizing axial forces, thereby providing a calculation approach for the stress and deformation of the foundation pit support system. Additionally, the developed axial force iterative calculation method was compared with numerical analysis methods to analyze the stress and deformation patterns in the support structure, which validated its effectiveness and accuracy.