scholarly journals ANALYSIS OF THE EXISTING NUMERICAL METHODS FOR MODELING THE INTERACTION OF THE WORKING BODIES OF DIGGING AND SOIL-PROCESSING MACHINES WITH SOIL MEDIA

2020 ◽  
Vol 3 (3) ◽  
pp. 128-139
Author(s):  
Maksim Gnusov ◽  
Mihail Lisich
Keyword(s):  
Numerical Methods ◽  
Software Products ◽  
Modern Computer ◽  
Particle Hydrodynamics ◽  
Soil Media ◽  
Computational Fluid Dynamics Cfd ◽  
Working Bodies ◽  
Cfd Method ◽  
The Cost ◽  
Element Method

Carrying out theoretical studies of the working processes of various machines and units today has ample opportunities when using modern computer technologies. The use of programs greatly speeds up the study of complex systems under study. The use of simulation methods is advisable when the cost of carrying out real experimental research is high or, due to certain circumstances, making research on a real system impossible, and the calculation of the analytical model will allow many assumptions and approximations that will affect the entire system and change it. In the article, special attention is paid to the selection of the most suitable modeling method for studying the process, liquidation of a forest fire with a flow of soil, using serial software products. The analysis of existing numerical methods for modeling the interaction of working bodies of earth-moving and tillage machines with soil media is carried out. The studies performed by the discrete element method (DEM), the finite element method (FEM), the computational fluid dynamics (CFD) method, and the smooth particle hydrodynamics (SPH) method are analyzed. Conclusions are drawn on the prospects for the applicability of each of the methods for modeling the system of processes of processing and throwing soil.

Aerodynamic Loading Induced by Muzzle Flows on Small Caliber Spin Stabilized Projectiles

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Chuanlin Chen ◽  
Hui Xu ◽  
Chenlei Huang ◽  
Zhongxin Li ◽  
Zhilin Wu
Keyword(s):  
High Speed ◽  
Exponential Relationship ◽  
Interior Ballistics ◽  
Aerodynamic Loading ◽  
Axial Forces ◽  
Pitch Moment ◽  
Temporal Pressure ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method ◽  
Element Method

Abstract In this study, we examined the aerodynamic loading on a small caliber rifle (spin stabilized) projectile moving in a muzzle flow field using an element method to analyze the loading and the effect of the angle of attack (for small angles from 0 to 3 deg) on the different components. The temporal pressure distribution on the projectile, which forms the basis of the element method, was computed using a computational fluid dynamics (CFD) analysis combined with a classical interior ballistics model. Then, a high-speed optical experiment was conducted to verify the results of the CFD method and ensure the accuracy of the calculations. The results were as follows: (a) similar to a large caliber projectile, the total axial force, which consisted primarily of the axial forces on the base and boattail, was found to have an inverse exponential relationship with time; (b) the overall lift was a combination of the lift of the base, boattail, cylinder, and nose; and (c) the interaction between the pitch moment of the base and that of the boattail was found to be the primary contributing factor to the total pitch moment. Based on these results, we recommend that the characteristics of the base and boattail be considered when specifying the geometric configuration of a projectile.

Towards Simulation of Clogging Effects in Wastewater Pumps: A Review of the State-of-the-Art in Cloth Modelling and Challenges in the Simulation of Clogging Effects

2015 ◽  
Author(s):  
Anna Lyhne Jensen ◽  
Lasse Rosendahl ◽  
Henrik Sørensen ◽  
Flemming Lykholt-Ustrup
Keyword(s):  
Immersed Boundary ◽  
Arbitrary Lagrangian Eulerian ◽  
Advantages And Disadvantages ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Computational Fluid Dynamics Cfd ◽  
Potential Methods ◽  
Future Work ◽  
Ib Method ◽  
Element Method

Simulation of clogging effects caused by cloths in wastewater pumps enables a faster and cheaper design process of wastewater pumps, which potentially leads to a reduction in the occurrence of clogging. Four potential methods for cloth simulation are reviewed and the challenges of each method are identified and compared. These methods are the Arbitrary Lagrangian-Eulerian (ALE) method, Immersed Boundary (IB) method, Smoothed Particle Hydrodynamics (SPH) coupled with the Finite Element method (FEM), and Computational Fluid Dynamics (CFD) coupled with the Discrete Element method (DEM). Each method has advantages and disadvantages, and each of them may prove to be applicable for the application. The CFD-DEM approach is chosen for future work.

scholarly journals Investigation of the Configuration of Small Hydropower using a Novel Smoothed Particle Hydrodynamics Method

2021 ◽  
Vol 945 (1) ◽  
pp. 012039
Author(s):  
Shu Kai Ng ◽  
Akihiko Nakayama
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Vertical Axis ◽  
Fluid Structure Interactions ◽  
Small Hydropower ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Smoothed Particle Hydrodynamics Method ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Through ◽  
Cfd Method

Abstract A novel Computational Fluid Dynamics (CFD) method utilizing Smoothed Particle Hydrodynamics (SPH) has been developed and applied to a simulation of flows in small hydropower systems. The simulation of the flow through a gravitational vortex turbine (GVT) small hydropower system where the flow is directed to a circular basin with a vertical-axis turbine, harnessing the rotational energy of the vortex formed to drive the turbine. Two modes of Fluid-Structure Interactions (FSI) were tested with identical flow conditions to evaluate the potential of this method to simulate complex FSI scenarios. It was found that simulation results for both one-way and two-way interactions produced reasonable results. The two-way interaction result proved to reflect more accurate FSI scenarios, but more studies are needed to provide validation.

THEORETICAL PRINCIPLES OF FORECASTING THE COST OF A SOFTWARE PRODUCT

2017 ◽  
Author(s):  
Pavlo Rodionov ◽  
◽  
Anna Ploskonos ◽  
Lesya Gavrutenko ◽  
◽  
...  
Keyword(s):  
Selection Process ◽  
Individual Characteristics ◽  
Successful Implementation ◽  
Software Products ◽  
Software Product ◽  
Continue Research ◽  
Cocomo Model ◽  
Factors Of Influence ◽  
The Individual ◽  
The Cost

The paper analyzes the factors that affect the amount of effort required to create a mobile application and its cost. It is established that the main factors of influence are the design of the application, its functionality, the type of mobile platform, the availability and level of testing and support, as well as the individual characteristics of the developer. Based on the analysis of information sources, the main methods and approaches to forecasting the cost of software products are identified, which include the COCOMO model, Price-to-win method, expert evaluation, algorithmic methods and the method of analogies. It is proposed to consider the method of analogies as a tool that allows you to make predictions about the cost of resources required for the successful implementation of IT projects based on the experience of similar projects. It is proved that the advantages of this method are the simplicity of its implementation and the clarity of the results obtained, which follows from the practical orientation of this tool. Among the limitations of the method of analogy is the mandatory need for reliable data relating to similar projects, as well as the difficulty of taking into account unspecified indicators. Taking into account the mentioned limitations of the method of analogies and on the basis of the analysis of scientific sources the possible directions of its optimization are determined. Thus, among the ways to improve the effectiveness of this method are those aimed at optimizing the project selection process, the data for which are used as a basis for forecasting. Attempts to improve the method of analogies by including parameters that were previously ignored by this technique seem promising. This in turn can lead to an expansion of the scope of the method of analogies and increase the accuracy of forecasts. As prospects for further research, the need to continue research in the field of optimization of the method of analogies with the subsequent practical verification of theoretical positions on the data of real projects.

Smoothed particle hydrodynamics versus finite element method for blast impact

2013 ◽  
Vol 61 (1) ◽  
pp. 111-121 ◽  
Author(s):  
T. Jankowiak ◽  
T. Łodygowski
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Smoothed Particle Hydrodynamics ◽  
Concrete Slab ◽  
The Finite Element Method ◽  
Particle Hydrodynamics ◽  
Mesh Density ◽  
Smoothed Particle ◽  
Element Method

Abstract The paper considers the failure study of concrete structures loaded by the pressure wave due to detonation of an explosive material. In the paper two numerical methods are used and their efficiency and accuracy are compared. There are the Smoothed Particle Hydrodynamics (SPH) and the Finite Element Method (FEM). The numerical examples take into account the dynamic behaviour of concrete slab or a structure composed of two concrete slabs subjected to the blast impact coming from one side. The influence of reinforcement in the slab (1, 2 or 3 layers) is also presented and compared with a pure concrete one. The influence of mesh density for FEM and the influence of important parameters in SPH like a smoothing length or a particle distance on the quality of the results are discussed in the paper

An anti-crystallization design of selective catalytic reduction nozzle holder

2021 ◽  
pp. 095440702097084
Author(s):  
Dewen Liu ◽  
Kai Lu ◽  
Shusen Liu ◽  
Yan Wu ◽  
Shuzhan Bai
Keyword(s):  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Injection System ◽  
Test Results ◽  
Verification Methods ◽  
Crystallization Risk ◽  
Protective Cover ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method ◽  
Good Agreement

From the aspect of reducing the risk of crystallization on nozzle surface, a new design of nozzle protective cover was to solve the problem in selective catalytic reduction (SCR) urea injection system. The simulation calculation and experimental verification methods were used to compare different schemes. The results show that reducing the height of nozzle holder can reduce the vortex currents near nozzle surface and effectively reduce the risk of crystallization on the nozzle surface. It is proposed to install a protective cover in the nozzle holder under the scheme of reducing the height of nozzle holder, which can further eliminate the vortex. Simulation and test results demonstrate good agreement under the rated running condition. The scheme of adding a protective cover in the nozzle holder shows the least crystallization risk by computational fluid dynamics (CFD) method. The crystallization cycle test shows that, after the height of nozzle holder is reduced, the risk of crystallization on the nozzle surface is reduced correspondingly. The addition of a protective cover in the nozzle holder solves the problem of crystallization on the nozzle surface, which provides a new method for anti-crystallization design.

Domains of Interference Between Working Bodies in Mechanisms and Manipulators

1995 ◽  
Author(s):  
Edward J. Haug ◽  
Frederick A. Adkins ◽  
Chi-Mei Luh ◽  
Jia-Yi Wang
Keyword(s):  
Numerical Methods ◽  
Jacobian Matrix ◽  
Underlying Mechanism ◽  
Rank Deficiency ◽  
Ground Vehicle ◽  
Complementary Problems ◽  
Stewart Platforms ◽  
Working Bodies ◽  
Set Of Points

Abstract Criteria for the set of all points in a pair of working bodies in a mechanism or manipulator that can coincide for any kinematically admissible configuration of the underlying mechanism, called the domain of interference between the bodies, are formulated. Kinematic equations for the mechanism and parameterizations of the domains of the working bodies are used to derive analytical criteria for domains of interference. Three complementary problems are formulated and analyzed to characterize (1) the set of points in one of the interfering bodies that are occupied by any point in the second body, (2) the set of points in one of the interfering bodies that are occupied by any point on the boundary of the second body, and (3) the set of all points in space that are simultaneously occupied by points in the interfering bodies; each condition occurring for any kinematically admissible configuration of the mechanism. Analytical criteria for the boundaries of domains of interference for each of the three problems arc derived, based on row-rank deficiency of a sub-Jacobian matrix associated with the kinematic equations for each of the problems. Numerical methods for mapping boundaries of domains of interference are presented and illustrated for planar Stewart platforms with domes attached that are characteristic of flight or ground vehicle simulators.

scholarly journals Multiscale Boundary Element Method for Acoustic Wave Model

MATEMATIKA ◽  
2019 ◽  
Vol 35 (3) ◽  
Author(s):  
Nor Afifah Hanim Zulkefli ◽  
Yeak Su Hoe ◽  
Munira Ismail
Keyword(s):  
Boundary Element Method ◽  
Numerical Methods ◽  
Acoustic Wave ◽  
Boundary Element ◽  
Computational Efficiency ◽  
Large Scale ◽  
Wave Model ◽  
Large Scale Problems ◽  
Speed Up ◽  
Element Method

In numerical methods, boundary element method has been widely used to solve acoustic problems. However, it suffers from certain drawbacks in terms of computational efficiency. This prevents the boundary element method from being applied to large-scale problems. This paper presents proposal of a new multiscale technique, coupled with boundary element method to speed up numerical calculations. Numerical example is given to illustrate the efficiency of the proposed method. The solution of the proposed method has been validated with conventional boundary element method and the proposed method is indeed faster in computation.

scholarly journals Validasi Model Turbulensi pada Simulasi Numerik Menggunakan Software Fluent dengan Sayap Onera M6

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Sulistiya Sulistiya ◽  
Alief Sadlie Kasman
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Computational Result ◽  
Computational Simulation ◽  
Turbulence Models ◽  
Wind Tunnels ◽  
Direct Testing ◽  
The World ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method

AbstractNumerical simulation using Computational Fluid Dynamics (CFD) method is one way of predicting airflow characteristics on the model. This method is widely used because it is relatively inexpensive and faster in getting desired results compared with performing direct testing. The correctness of a computational simulation output is highly dependent on the input and how it was processed. In this paper, simulation is done on Onera M6 Wing, to investigate the effect of a turbulence model’s application on the accuracy of the computational result. The choice of Onera M6 Wing as a simulation’s model is due to its extensive database of testing results from various wind tunnels in the world. Among Turbulence models used are Spalart-Allmaras, K-Epsilon, K-Omega, and SST.Keywords: CFD, fluent, Model, Turbulence, Onera M6, Spalart-Allmaras, K-Epsilon, K-Omega, SST.AbstraksSimulasi numerik dengan menggunakan metode Computational Fluid Dynamics (CFD) merupakan salah satu cara untuk memprediksi karakteristik suatu aliran udara yang terjadi pada model. Metode ini banyak digunakan karena sifatnya yang relatif murah dan cepat untuk mendapatkan hasil dibandingkan dengan melakukan pengujian langsung. Benar tidak hasil sebuah simulasi komputasi sangat tergantung pada inputan yang diberikan serta cara memproses data inputan tersebut. Pada tulisan ini dilakukan simulasi dengan menggunakan sayap onera M6 dengan tujuan untuk mengetahui pengaruh penggunaan model turbulensi terhadap keakuratan hasil komputasi. Pilihan sayap onera M6 sebagai model simulasi dikarenakan model tersebut sudah memiliki database hasil pengujian yang cukup lengkap dan sudah divalidasi dari berbagai terowongan angin di dunia. Model turbulensi yang digunakan diantaranya Spalart-Allmaras, K-Epsilon, K-Omega dan SST.Kata Kunci : CFD, fluent, Model, Turbulensi, Onera M6, Spalart-Allmaras, K-Epsilon, K-Omega, SST.

scholarly journals Application of the optimally alloyed cast irons in order to increase the durability and to ensure the cost reduction of mining and metallurgical products

2021 ◽  
Vol 303 ◽  
pp. 01005
Author(s):  
Dmitry Lubyanoi ◽  
Evgeny Pudov ◽  
Evgeny Kuzin ◽  
Olga Semenova
Keyword(s):  
Wear Resistance ◽  
Cast Iron ◽  
Operational Reliability ◽  
Cast Irons ◽  
Metallurgical Production ◽  
Alloyed Cast ◽  
Alloyed Cast Iron ◽  
And Performance ◽  
Working Bodies ◽  
The Cost

The article shows the relevance of the use of alloyed cast iron in mining and metallurgical engineering. The article discusses the technologies for producing naturally alloyed cast iron. For working bodies and friction units of mining machines, such as pumps, coal pumps, hydrocyclones, crushers and mills. The main type of wear for them is abrasive. To increase the wear resistance of cast iron the production of cast iron has not been sufficiently studied yet. Although the use of cast iron in a complex alloyed with manganese, silicon, chromium, titanium and vanadium has been studied. The article studies the influence of manganese, titanium and vanadium on the mechanical properties and performance of machine parts and products of mining and metallurgical production in contact with high-temperature and highly abrasive media. The rational content of titanium and vanadium in gray cast irons is established in the range of 0.05-0.1%, which ensures their heat resistance and increases their wear resistance. The content of these elements can be increased to 0.07-0.12%. Bushings made of this cast iron have the required wear resistance and can increase the operational reliability of the equipment in the conditions of mining and metallurgical production. They also replace non-ferrous metals, as well as products obtained by powder metallurgy methods.

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