scholarly journals OPTIMIZATION PARAMETERS OF IRRIGATION PROCESS ACCORDING TO THE UNIFORMITY

2012 ◽  
Vol 15 (1) ◽  
pp. 80-89
Author(s):  
Tuyen Vo ◽  
Nam Thanh Nguyen ◽  
Lien Duc Hoang
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Experimental Determination ◽  
Optimal Parameters ◽  
Optimization Parameters ◽  
Simulation Results

In order to determine the optimal parameters of irrigation process in order to verify the accuracy of the numerical simulation results of experimental determination of the effective spray during irrigation [2], [6]. This paper will conduct empirical planning, establishing empirical mathematical model to determine the diameter of the nozzle, swirl coefficient and irrigation output according to the uniformity.

scholarly journals Population Behavior in the Mathematical Model of the Spread of COVID19 Type SEIRS

2021 ◽  
Vol 6 (2) ◽  
pp. 83-88
Author(s):  
Asmaidi As Med ◽  
Resky Rusnanda
Keyword(s):  
Mathematical Modeling ◽  
Numerical Simulation ◽  
Mathematical Model ◽  
Everyday Life ◽  
Applied Mathematics ◽  
Living Things ◽  
Simulation Results ◽  
Parameter Values ◽  
The Mathematical Model ◽  
Disease Free

Mathematical modeling utilized to simplify real phenomena that occur in everyday life. Mathematical modeling is popular to modeling the case of the spread of disease in an area, the growth of living things, and social behavior in everyday life and so on. This type of research is included in the study of theoretical and applied mathematics. The research steps carried out include 1) constructing a mathematical model type SEIRS, 2) analysis on the SEIRS type mathematical model by using parameter values for conditions 1and , 3) Numerical simulation to see the behavior of the population in the model, and 4) to conclude the results of the numerical simulation of the SEIRS type mathematical model. The simulation results show that the model stabilized in disease free quilibrium for the condition  and stabilized in endemic equilibrium for the condition .

Research on the Numerical Simulation of Silting in Floodplain and Scouting in Main Channel of Over-Bank Flooding in the Lower Yellow River

2011 ◽  
Vol 255-260 ◽  
pp. 3692-3696
Author(s):  
Xiao Lei Zhang ◽  
Dong Po Sun ◽  
Feng Ran Zhang
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Yellow River ◽  
Main Channel ◽  
River Channel ◽  
Lower Yellow River ◽  
The Lower Yellow River ◽  
Water And Sediment ◽  
Simulation Results ◽  
Set Up

The 2-D water and sediment mathematical model which reflects silting in floodplain and scouting in main channel of over-bank flooding in the Lower Yellow River has been set up in this paper. Through carrying on 2-D water and sediment numerical simulation of the “96.8” typical flood, the author studied influence of over-bank flooding on flood travel and transverse exchange. The primary simulation results show that, adopting the over-bank flooding for silting in floodplain and scouting in main channel effectively guaranteed and expanded transverse exchange between floodplain and main channel and maintained the river channel vigor. This can relieve “secondary suspended river” states in the Low Yellow River to a certain extent; at the same time, the different magnitudes of over-bank floods have different effect of silting in floodplain and scouting in main channel.

Vibrations of a Double Beam Structure Carrying a High-Pressure Driven Projectile

2019 ◽  
Author(s):  
Alexander Khair ◽  
Bingen Yang
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
High Pressure ◽  
Dynamic Stress ◽  
Beam Theory ◽  
Weapon System ◽  
Beam Structure ◽  
Double Beam ◽  
Simulation Results ◽  
Pressure Driven

Abstract In this paper, a mathematical model of a double beam structure carrying a high-pressure driven projectile is developed for investigation of the physical behaviors of gun barrels during firing. The dynamic response of such a weapon system is particularly interesting when reduction of muzzle vibrations and relevant dynamic stress in the structure is needed to improve the life cycle of the gun. In the model presented, the Timoshenko beam theory is implemented, and realistic characteristics of the physical system are considered. Numerical simulation results are presented for the displacement and rotation of the two beams, and the rigid-body projectile mass.

scholarly journals Initial Value Determination of Chua System with Hidden Attractors and Its DSP Implementation

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Xianming Wu ◽  
Weijie Tan ◽  
Huihai Wang
Keyword(s):  
Numerical Simulation ◽  
Digital Signal Processor ◽  
Digital Signal ◽  
Hidden Attractors ◽  
Initial Value ◽  
Circuit Realization ◽  
Dsp Implementation ◽  
Simulation Results ◽  
Value Determination

In this paper, a method for determining the initial value of the hidden attractors in the Chua system is studied. The initial value of the hidden attractors can be calculated quickly and accurately by the proposed method, and the hidden attractors can be found by numerical simulation. Then, the initial values of the hidden attractors are set accurately by digital signal processor (DSP), so as to the circuit realization of the chaotic system with hidden attractors is performed. The results show that the numerical simulation results of Matlab are consistent with the experimental results of DSP.

Numerical Simulation of Seepage Field in Aquifer under the Coal Seam

2014 ◽  
Vol 955-959 ◽  
pp. 3120-3124
Author(s):  
Kai Bian ◽  
Shi Lei Chen ◽  
Xue Yuan Li ◽  
Ying Wang Zhao
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Coal Seam ◽  
Three Dimensional ◽  
Seepage Field ◽  
Limestone Aquifer ◽  
Flow Models ◽  
Hydrogeological Parameters ◽  
Simulation Results ◽  
Technical Basis

In order to figure out seepage field in aquifer under the coal seam, the geology and hydrogeology conditions systematically of study area were analyzed, hydrogeological conceptual model was generalized, mathematical model was built, seepage field of the Taiyuan limestone aquifer was simulated with software Feflow. Simulation results show that hydrogeological parameters of Taiyuan limestone aquifer change greatly in different partitions. The model also indicates the heterogeneity of karst fissure of Taiyuan limestone aquifer. The drainage quantity is from the Ordovician limestone aquifer besides supplying from runoff of upstream and capture excretion of downstream. The research is an attempt to simulate the seepage field in aquifer under coal seam, to some extent, it also provides a technical basis for safe coal mining and as a reference for simulation constructions of three-dimensional groundwater flow models in similar coal mines.

scholarly journals Deactivation by sintering of the cobalt catalyst during the Fischer-Tropsch reaction

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Dounia Alihellal ◽  
Lemnouer Chibane ◽  
Mohamed El-Amine Slimani
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Active Sites ◽  
Cobalt Catalyst ◽  
Reaction Rates ◽  
Operating Conditions ◽  
Molar Ratio ◽  
Fischer Tropsch ◽  
Simulation Results ◽  
By Products

In the present work, the deactivation by sintering of cobalt-based catalyst during Fischer-Tropsch synthesis at low temperature was studied by numerical simulation. For this purpose, a mathematical model was developed. The obtained simulation results allowed us to highlight and improve the understanding of the deactivation phenomena of cobalt-based Fischer-Tropsch catalysts by sintering. The main results also show that the sintering phenomenon is strongly dependent on the operating conditions, in particular, the temperature, the pressure, and the H2/CO molar ratio, as well as the reaction by-products such as water. The results obtained can, therefore, be used to understand more the sintering mechanism which may be linked to the change in the concentration of the active sites and the reaction rates.

scholarly journals PROCESSING OF OIL WELL PRESSURE RECOVERY CURVES

2019 ◽  
pp. 18-20
Author(s):  
Abasova Inara Afrail
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Pressure Recovery ◽  
Oil Well ◽  
Recovery Curve ◽  
Recovery Curves ◽  
Reservoir Permeability ◽  
Curve Change ◽  
Industry Conditions

In the article the development of a mathematical model describing the PRC is studied on the base of pressure recovery curve method.Detailed processing of the pressure recovery curve made it possible to determine the deterioration of reservoir permeability in many wells. Here two methods are considered - stationary (steady conditions of selection) and non- stationary.The article proves that the use of these methods allows to develop a mathematical model to increase the determination of this task.On the base of numerical simulation, the following facts had impact on the results of the pressure recovery curve: well shutdown time, taking into account the initial transition section, taking into account curve change section before well shutdown.The study of variable factors impact on the results is carried out by interval estimation.The mathematical model describing the pressure recovery curve is local and changes its structures. This model can be used in industry conditions.

scholarly journals Methodology for determining the parameters of drilling mode for directional straight sections of well using screw downhole motors

2020 ◽  
Vol 241 ◽  
pp. 105 ◽  
Author(s):  
V. Litvinenko ◽  
M. Dvoinikov
Keyword(s):  
Mathematical Model ◽  
Stable Operation ◽  
Geometrical Parameters ◽  
Directional Drilling ◽  
Optimal Parameters ◽  
Combined Method ◽  
Steady State Operation ◽  
Drilling String ◽  
Simultaneous Rotation

Article presents results of study on possibility of increasing the efficiency of drilling directional straight sections of wells using screw downhole motors (SDM) with a combined method of drilling with rotation of drilling string (DS). Goal is to ensure steady-state operation of SDM with simultaneous rotation of DS by reducing the amplitude of oscillations with adjusting the parameters of drilling mode on the basis of mathematical modeling for SDM – DS system.Results of experimental study on determination of extrema distribution of lateral and axial oscillations of SDM frame depending on geometrical parameters of gerotor mechanism and modes ensuring stable operation are presented.Approaches to development of a mathematical model and methodology are conceptually outlined that allow determining the range of self-oscillations for SDM – DS system and boundaries of rotational and translational wave perturbations for a heterogeneous rod with an installed SDM at drilling directional straight sections of well. This mathematical model of SDM – DS system's dynamics makes it possible to predict optimal parameters of directional drilling mode that ensure stable operation of borehole assembly.  

Accurate Determination of Critical Safety Height During Available Safe Egress Time Assessment

2016 ◽  
Vol 13 (10) ◽  
pp. 7545-7547
Author(s):  
Xuefeng Han ◽  
Yao Deng ◽  
Xiaomei Wang ◽  
Juncheng Jiang
Keyword(s):  
Numerical Simulation ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Accurate Determination ◽  
Hazard Index ◽  
Simulation Results ◽  
Time Assessment ◽  
Selection Of

When evaluating the ASET (available safe egress time), the fire scenario and the heat release rate (HRR) of the fire need to be set firstly according to the function and the combustible materials of the building, then CFD (Computational Fluent Dynamics) software is used to perform simulations. The ASET is obtained at the time when the hazard index of smoke reaches the minimum value at a safety height, and this height could be defined as critical safety height. It is very important to select critical safety height and heat release rate for the accuracy of the simulation results. The variation of selection of the critical safety height in references is large and it is lacking of credible evidence. This paper discusses the critical safety height based on statistics, probability and ergonomicsvvso as to improve the accuracy, credibility and reliability of the numerical simulation.

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