Pub Date : 2017-12-20DOI: 10.5772/INTECHOPEN.71956
Armando Martínez-Pérez, G. Torres-Vega
We introduce a finite difference derivative, on a non-uniform partition, with the characteristic that the derivative of the exponential function is the exponential function itself, times a constant, which is similar to what happens in the continuous variable case. Aside from its application to perform numerical computations, this is particularly useful in defining a quantum mechanical discrete momentum operator.
{"title":"Exact Finite Differences for Quantum Mechanics","authors":"Armando Martínez-Pérez, G. Torres-Vega","doi":"10.5772/INTECHOPEN.71956","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.71956","url":null,"abstract":"We introduce a finite difference derivative, on a non-uniform partition, with the characteristic that the derivative of the exponential function is the exponential function itself, times a constant, which is similar to what happens in the continuous variable case. Aside from its application to perform numerical computations, this is particularly useful in defining a quantum mechanical discrete momentum operator.","PeriodicalId":103650,"journal":{"name":"Numerical Simulations in Engineering and Science","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132346805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-12-20DOI: 10.5772/INTECHOPEN.71528
D. Munteanu, J. Autran
New semiconductor materials are envisaged in numerous high-performance applica- tions for which the expected device or circuit performances cannot be achieved with silicon. In this context of growing use of new and specific semiconductors, the question of their susceptibility to natural radiation, primarily to atmospheric neutrons, is posed for high-reliability-level application domains. This numerical simulation work precisely examines nuclear events resulting from the interaction of atmospheric neutrons at the terrestrial level with a target layer composed of various group-IV and III-V semicon- ductor materials including silicon, germanium, silicon carbide, carbon-diamond, gal lium arsenide, and gallium nitride materials. Using extensive Geant4 simulations and in-depth data analysis, this study provides an accurate and fine comparison between the neutron interaction responses of these different semiconductors in terms of nuclear processes, recoil products, secondary ion production, and fragment energy distributions. Implications of these results on the rate of single-event transient effects at the device or circuit level are also discussed. alpha particles, characterized by lower LET values but longer ranges in the different semicon ductor materials, are susceptible to induce single events farther from their emission point than heavy fragments up to distances of hundred microns for alpha particles and several millimeters for protons. Finally, the consequences of neutron interactions in the different targets in terms of electron–hole pair generation, a fundamental mechanism at the origin of single events in electronics, have been examined. Our results show that germanium cor responds to the worst case and diamond (also SiC) to the best case with regard to e–h pair production, Si, GaAs, and GaN being relatively equivalent and of intermediate behavior with respect to this criterion.
{"title":"Susceptibility of Group-IV and III-V Semiconductor-Based Electronics to Atmospheric Neutrons Explored by Geant4 Numerical Simulations","authors":"D. Munteanu, J. Autran","doi":"10.5772/INTECHOPEN.71528","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.71528","url":null,"abstract":"New semiconductor materials are envisaged in numerous high-performance applica- tions for which the expected device or circuit performances cannot be achieved with silicon. In this context of growing use of new and specific semiconductors, the question of their susceptibility to natural radiation, primarily to atmospheric neutrons, is posed for high-reliability-level application domains. This numerical simulation work precisely examines nuclear events resulting from the interaction of atmospheric neutrons at the terrestrial level with a target layer composed of various group-IV and III-V semicon- ductor materials including silicon, germanium, silicon carbide, carbon-diamond, gal lium arsenide, and gallium nitride materials. Using extensive Geant4 simulations and in-depth data analysis, this study provides an accurate and fine comparison between the neutron interaction responses of these different semiconductors in terms of nuclear processes, recoil products, secondary ion production, and fragment energy distributions. Implications of these results on the rate of single-event transient effects at the device or circuit level are also discussed. alpha particles, characterized by lower LET values but longer ranges in the different semicon ductor materials, are susceptible to induce single events farther from their emission point than heavy fragments up to distances of hundred microns for alpha particles and several millimeters for protons. Finally, the consequences of neutron interactions in the different targets in terms of electron–hole pair generation, a fundamental mechanism at the origin of single events in electronics, have been examined. Our results show that germanium cor responds to the worst case and diamond (also SiC) to the best case with regard to e–h pair production, Si, GaAs, and GaN being relatively equivalent and of intermediate behavior with respect to this criterion.","PeriodicalId":103650,"journal":{"name":"Numerical Simulations in Engineering and Science","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132465322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-12-20DOI: 10.5772/INTECHOPEN.71139
N. Aleksandr, K. Maria, Karpov Mikhail, ZolotovOleg, Martynenko Oleg, Yurik Roman, Foerster Matthias, P. Boris
The global numerical first principle 3D model of the upper atmosphere (UAM) for the heights 60–100,000 km is presented. The physical continuity, motion, heat balance and electric potential equations for the neutral, ion and electron gases and their numerical solution method are described. The numerical grids, spatial and time integration steps are given together with the boundary and initial conditions and inputs. Testing and obtained geophysical results are given for many observed situations at various levels of solar, geomagnetic and seismic activity. and in the magnetosphere tail via the magnetic field lines reconnection processes and connected with the polar upper atmosphere in the auroral zones via FACs including the current wedges. The substorm auroral currents are reflected by the auroral magnetic activity indexes AL , AU and AE . The UAM takes into account these indexes. This allows the modeling of the upper atmospheric behavior during substorms via the UAM simulations. The results were presented in [4, 48–53] including the cusp and auroral oval behavior, energetic magnetospheric electron precipitations, electric fields, current wedge and internal atmospheric gravity waves generation. The main role of the thermospheric heating due to the soft electron precipitation was shown for the thermosphere substorm effects.
{"title":"The Global Numerical Model of the Earth’s Upper Atmosphere","authors":"N. Aleksandr, K. Maria, Karpov Mikhail, ZolotovOleg, Martynenko Oleg, Yurik Roman, Foerster Matthias, P. Boris","doi":"10.5772/INTECHOPEN.71139","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.71139","url":null,"abstract":"The global numerical first principle 3D model of the upper atmosphere (UAM) for the heights 60–100,000 km is presented. The physical continuity, motion, heat balance and electric potential equations for the neutral, ion and electron gases and their numerical solution method are described. The numerical grids, spatial and time integration steps are given together with the boundary and initial conditions and inputs. Testing and obtained geophysical results are given for many observed situations at various levels of solar, geomagnetic and seismic activity. and in the magnetosphere tail via the magnetic field lines reconnection processes and connected with the polar upper atmosphere in the auroral zones via FACs including the current wedges. The substorm auroral currents are reflected by the auroral magnetic activity indexes AL , AU and AE . The UAM takes into account these indexes. This allows the modeling of the upper atmospheric behavior during substorms via the UAM simulations. The results were presented in [4, 48–53] including the cusp and auroral oval behavior, energetic magnetospheric electron precipitations, electric fields, current wedge and internal atmospheric gravity waves generation. The main role of the thermospheric heating due to the soft electron precipitation was shown for the thermosphere substorm effects.","PeriodicalId":103650,"journal":{"name":"Numerical Simulations in Engineering and Science","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128501812","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-12-20DOI: 10.5772/INTECHOPEN.70706
K. Mehboob, M. S. Aljohani
The aim of this work is to carry out the numerical simulation of fission product (FP) behavior inside the reactor building under loss of coolant accident (LOCA) using MATLAB. For this purpose, a kinetic model has been developed and implemented in MATLAB to study the behavior of in-containment FPs during postulated LOCA for typical 1000 MW pressurized water reactor (PWR). A continuous release of the FPs from the reactor pressure vessel (RPV) has been implemented with coolant retention. The in-containment FP behavior is influenced by containment atmosphere and contain- ment safety systems. The sensitivity analysis and removal rate of airborne isotopes with the containment spray system have been studied for various spray activation time, spray failure time, droplet size and spray pH value. The droplet size and pH value of the spray system effectively remove the airborne isotopes. The alkaline (sodium thiosulfate, Na 2 S 2 O 3 ) spray solution and spray with pH 9.5 have similar scrubbing properties for iodine. However, the removal rate from the containment spray system has been found an approximately inverse square of droplet diameter (1/d 2 ).
{"title":"Numerical Simulation of Fission Product Behavior Inside the Reactor Containment Building Using MATLAB","authors":"K. Mehboob, M. S. Aljohani","doi":"10.5772/INTECHOPEN.70706","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.70706","url":null,"abstract":"The aim of this work is to carry out the numerical simulation of fission product (FP) behavior inside the reactor building under loss of coolant accident (LOCA) using MATLAB. For this purpose, a kinetic model has been developed and implemented in MATLAB to study the behavior of in-containment FPs during postulated LOCA for typical 1000 MW pressurized water reactor (PWR). A continuous release of the FPs from the reactor pressure vessel (RPV) has been implemented with coolant retention. The in-containment FP behavior is influenced by containment atmosphere and contain- ment safety systems. The sensitivity analysis and removal rate of airborne isotopes with the containment spray system have been studied for various spray activation time, spray failure time, droplet size and spray pH value. The droplet size and pH value of the spray system effectively remove the airborne isotopes. The alkaline (sodium thiosulfate, Na 2 S 2 O 3 ) spray solution and spray with pH 9.5 have similar scrubbing properties for iodine. However, the removal rate from the containment spray system has been found an approximately inverse square of droplet diameter (1/d 2 ).","PeriodicalId":103650,"journal":{"name":"Numerical Simulations in Engineering and Science","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116639432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-12-20DOI: 10.5772/INTECHOPEN.70810
H. Yokoyama, A. Iida
Aeroacoustic simulations are divided into hybrid and direct simulations. In this chapter, the effects of freestream Mach number on flow and acoustic fields around a two-dimensional square cylinder in a uniform flow are focused on using direct and hybrid simulations of flow and acoustic fields are performed. These results indicate the effectiveness and limit of the hybrid simulations. The Mach number M is varied from 0.2 to 0.6. The propagation angle of the acoustic waves for a high Mach number such as M = 0.6 greatly differs from that predicted by modified Curle ’ s equation, which assumes the scattered sound to be dominant and takes the Doppler effects into consideration. This is because the acoustic field is affected by the direct sound, which is generated by quadrupoles in the original Curle ’ s equation. To clarify the effects of the direct sound on the acoustic field, the scattered and direct sounds are decomposed. The results show that the direct sound is too intense to neglect for M ≥ 0.4. Moreover, acoustic simulations are performed using the Lighthill ’ s acoustic sources.
{"title":"Direct and Hybrid Aeroacoustic Simulations Around a Rectangular Cylinder","authors":"H. Yokoyama, A. Iida","doi":"10.5772/INTECHOPEN.70810","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.70810","url":null,"abstract":"Aeroacoustic simulations are divided into hybrid and direct simulations. In this chapter, the effects of freestream Mach number on flow and acoustic fields around a two-dimensional square cylinder in a uniform flow are focused on using direct and hybrid simulations of flow and acoustic fields are performed. These results indicate the effectiveness and limit of the hybrid simulations. The Mach number M is varied from 0.2 to 0.6. The propagation angle of the acoustic waves for a high Mach number such as M = 0.6 greatly differs from that predicted by modified Curle ’ s equation, which assumes the scattered sound to be dominant and takes the Doppler effects into consideration. This is because the acoustic field is affected by the direct sound, which is generated by quadrupoles in the original Curle ’ s equation. To clarify the effects of the direct sound on the acoustic field, the scattered and direct sounds are decomposed. The results show that the direct sound is too intense to neglect for M ≥ 0.4. Moreover, acoustic simulations are performed using the Lighthill ’ s acoustic sources.","PeriodicalId":103650,"journal":{"name":"Numerical Simulations in Engineering and Science","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129642390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-12-20DOI: 10.5772/INTECHOPEN.71230
J. Stajnko, R. Jecl, J. Ravnik
In this chapter, the boundary element method (BEM) is introduced for solving prob- lems of transport phenomena in porous media domains, which is an important topic in many engineering and scientific branches as well as in fields of practical interest. The main objective of the present work is to find a numerical solution of the governing set of equations written for fluid flow in porous media domains, representing conserva - tion of mass, momentum, and energy. The momentum equation is based on the mac roscopic Navier-Stokes equations and is coupled with the energy equation. In order to use BEM for the solution of the obtained set, the governing equations are transformed by the velocity-vorticity formulation, which separates the computational scheme into kinematic and kinetic computational parts. A combination of single- and sub-domain BEM is used to solve the obtained set of partial differential equations. Solution to a problem of natural convection in porous media saturated with pure fluid and nanofluid, respectively, for examples of 2D and 3D geometries, is shown. Results are compared to published work in order to estimate the accuracy of developed numerical algorithm. Based on the results, the applicability of the BEM for solving wide range of various problems is stated.
{"title":"Simulation of Natural Convection in Porous Media by Boundary Element Method","authors":"J. Stajnko, R. Jecl, J. Ravnik","doi":"10.5772/INTECHOPEN.71230","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.71230","url":null,"abstract":"In this chapter, the boundary element method (BEM) is introduced for solving prob- lems of transport phenomena in porous media domains, which is an important topic in many engineering and scientific branches as well as in fields of practical interest. The main objective of the present work is to find a numerical solution of the governing set of equations written for fluid flow in porous media domains, representing conserva - tion of mass, momentum, and energy. The momentum equation is based on the mac roscopic Navier-Stokes equations and is coupled with the energy equation. In order to use BEM for the solution of the obtained set, the governing equations are transformed by the velocity-vorticity formulation, which separates the computational scheme into kinematic and kinetic computational parts. A combination of single- and sub-domain BEM is used to solve the obtained set of partial differential equations. Solution to a problem of natural convection in porous media saturated with pure fluid and nanofluid, respectively, for examples of 2D and 3D geometries, is shown. Results are compared to published work in order to estimate the accuracy of developed numerical algorithm. Based on the results, the applicability of the BEM for solving wide range of various problems is stated.","PeriodicalId":103650,"journal":{"name":"Numerical Simulations in Engineering and Science","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126318994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-12-20DOI: 10.5772/INTECHOPEN.71202
Leiyong Jiang, Yinghua Han, M. Capurro, M. Benner
The beauty of numerical simulations is its ability to reveal the physics or nature of practi- cal engineering problems in detail, and then, to identify adequate solutions. In this chapter, an excellent example is demonstrated. The rupture of a heavy-duty, high-pressure natural gas heat exchanger is numerically investigated, and the importance of gravity effect is identified, which is often considered as a trivial factor. For the original design, the natural convection in the flow field of the heat exchanger is comparable with the forced convection at the designed operating conditions. These two convections are per - pendicular and compete with each other, the flow field is highly unsteady, and high-temperature natural gas is trapped in the upper portion of the vessel, which causes the damage of the exchanger. By vertically mounting the exchanger assembly and locating the outlet pipe on top of the exchanger, the flow parameters become rather uniform at each vertical cross section and the wall temperature of the heat exchanger remains more or less the same as the heated natural gas. The proposed design has been successfully used up to now.
{"title":"Failure Analysis of a High-Pressure Natural Gas Heat Exchanger and its Modified Design","authors":"Leiyong Jiang, Yinghua Han, M. Capurro, M. Benner","doi":"10.5772/INTECHOPEN.71202","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.71202","url":null,"abstract":"The beauty of numerical simulations is its ability to reveal the physics or nature of practi- cal engineering problems in detail, and then, to identify adequate solutions. In this chapter, an excellent example is demonstrated. The rupture of a heavy-duty, high-pressure natural gas heat exchanger is numerically investigated, and the importance of gravity effect is identified, which is often considered as a trivial factor. For the original design, the natural convection in the flow field of the heat exchanger is comparable with the forced convection at the designed operating conditions. These two convections are per - pendicular and compete with each other, the flow field is highly unsteady, and high-temperature natural gas is trapped in the upper portion of the vessel, which causes the damage of the exchanger. By vertically mounting the exchanger assembly and locating the outlet pipe on top of the exchanger, the flow parameters become rather uniform at each vertical cross section and the wall temperature of the heat exchanger remains more or less the same as the heated natural gas. The proposed design has been successfully used up to now.","PeriodicalId":103650,"journal":{"name":"Numerical Simulations in Engineering and Science","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114560050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-12-20DOI: 10.5772/INTECHOPEN.71364
I. Astefanoaei, A. Stancu
The numerical and/or analytical modeling of the temperature field developed by the magnetic systems in the external alternating magnetic fields is essential in the Magnetic Hyperthermia. Optimization of the all parameters involved in the burning process of the malignant tissues can be realized more efficiently using a mathematical model. The analytical models can be used for the validation of any numerical complex models of the heating processes. This work focuses on the parameters which influences the therapeu tic temperature field developed by the magnetic systems within the malignant tissues when the magnetic field is applied. An analytical model was developed to predict and control the bioheat transport within a malignant tissue. This model was compared with a numerical model which was developed in the same conditions of the thermal analysis. Infusion of a diluted suspension of magnetic nanoparticles (MNP) into liver tissue was modeled using the Darcy’s equation. The MNP concentration and the temperature field were computed for different parameters as: (i) ferrofluid infusion rates, (ii) particle zeta potential and (iii) magnetic field parameters. The convection-diffusion-deposition of the particles within tissues was considered in this analysis. This study indicates the essential role of these parameters to predict accurately the hyperthermic temperature field. The model presented in this paper predicts the optimum MNP dosage and the temperature at every point within the malignant tissue.
{"title":"Modeling of the Temperature Field in the Magnetic Hyperthermia","authors":"I. Astefanoaei, A. Stancu","doi":"10.5772/INTECHOPEN.71364","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.71364","url":null,"abstract":"The numerical and/or analytical modeling of the temperature field developed by the magnetic systems in the external alternating magnetic fields is essential in the Magnetic Hyperthermia. Optimization of the all parameters involved in the burning process of the malignant tissues can be realized more efficiently using a mathematical model. The analytical models can be used for the validation of any numerical complex models of the heating processes. This work focuses on the parameters which influences the therapeu tic temperature field developed by the magnetic systems within the malignant tissues when the magnetic field is applied. An analytical model was developed to predict and control the bioheat transport within a malignant tissue. This model was compared with a numerical model which was developed in the same conditions of the thermal analysis. Infusion of a diluted suspension of magnetic nanoparticles (MNP) into liver tissue was modeled using the Darcy’s equation. The MNP concentration and the temperature field were computed for different parameters as: (i) ferrofluid infusion rates, (ii) particle zeta potential and (iii) magnetic field parameters. The convection-diffusion-deposition of the particles within tissues was considered in this analysis. This study indicates the essential role of these parameters to predict accurately the hyperthermic temperature field. The model presented in this paper predicts the optimum MNP dosage and the temperature at every point within the malignant tissue.","PeriodicalId":103650,"journal":{"name":"Numerical Simulations in Engineering and Science","volume":"GE-24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126566124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-12-20DOI: 10.5772/INTECHOPEN.71026
A. Khoperskov, S. Khrapov
In current chapter, we have thoroughly described a numerical integration scheme of nonstationary 2D equations of shallow water. The scheme combines the smoothed particle hydrodynamics (SPH) and the total variation diminishing (TVD) methods, which are sequentially used at various steps of the combined SPH-TVD algorithm. The method is conservative and well balanced. It provides stable through calculations in presence of nonstationary “water-dry bottom” boundaries on complex irregular bottom topography including the transition of such a boundary between wet and dry bottom through the computational boundary. Multifarious tests demonstrate the effectiveness of the combined SPH-TVD scheme application for a solution of diverse problems of the engineering hydrology.
{"title":"A Numerical Simulation of the Shallow Water Flow on a Complex Topography","authors":"A. Khoperskov, S. Khrapov","doi":"10.5772/INTECHOPEN.71026","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.71026","url":null,"abstract":"In current chapter, we have thoroughly described a numerical integration scheme of nonstationary 2D equations of shallow water. The scheme combines the smoothed particle hydrodynamics (SPH) and the total variation diminishing (TVD) methods, which are sequentially used at various steps of the combined SPH-TVD algorithm. The method is conservative and well balanced. It provides stable through calculations in presence of nonstationary “water-dry bottom” boundaries on complex irregular bottom topography including the transition of such a boundary between wet and dry bottom through the computational boundary. Multifarious tests demonstrate the effectiveness of the combined SPH-TVD scheme application for a solution of diverse problems of the engineering hydrology.","PeriodicalId":103650,"journal":{"name":"Numerical Simulations in Engineering and Science","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126652191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-12-20DOI: 10.5772/INTECHOPEN.71226
K. Masuda, Dai-heng Chen
In this chapter, thin-walled rectangular tubes under pure bending are considered, by per- forming a series of FEM numerical studies. In the simulation, a homogeneous and isotropic elastic perfectly plastic material was employed for the tube material. A commonly used method for predicting the collapse load of rectangular tubes subjected to pure bending was proposed by Kecman. Kecman’s method focuses on a slenderness of the flange. When buckling occurs in the flange, this method uses a collapse load corresponding to the post buckling strength of the flange. When buckling does not occur at the flange, this method used a relation of the flange slenderness to the cross-sectional fully plastic yielding. This method for predicting the collapse loads is effective when the aspect ratio of web to flange is not large. However, for large aspect ratios, there is a large discrepancy between the values of maximum moment corresponding to the collapse loads obtained from this method and the FEM numerical results due to an effect of web slenderness. A new method is proposed to predict the maximum moment considering the effect of web slenderness. The validity of the collapse load estimation is checked by the results of FEM numerical simulation. method, algorithm based on the Newton–Raphson method, and return-mapping method were used. The tubes were meshed using four-node (Element with five points across the A was
{"title":"Collapse Load for Thin-Walled Rectangular Tubes","authors":"K. Masuda, Dai-heng Chen","doi":"10.5772/INTECHOPEN.71226","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.71226","url":null,"abstract":"In this chapter, thin-walled rectangular tubes under pure bending are considered, by per- forming a series of FEM numerical studies. In the simulation, a homogeneous and isotropic elastic perfectly plastic material was employed for the tube material. A commonly used method for predicting the collapse load of rectangular tubes subjected to pure bending was proposed by Kecman. Kecman’s method focuses on a slenderness of the flange. When buckling occurs in the flange, this method uses a collapse load corresponding to the post buckling strength of the flange. When buckling does not occur at the flange, this method used a relation of the flange slenderness to the cross-sectional fully plastic yielding. This method for predicting the collapse loads is effective when the aspect ratio of web to flange is not large. However, for large aspect ratios, there is a large discrepancy between the values of maximum moment corresponding to the collapse loads obtained from this method and the FEM numerical results due to an effect of web slenderness. A new method is proposed to predict the maximum moment considering the effect of web slenderness. The validity of the collapse load estimation is checked by the results of FEM numerical simulation. method, algorithm based on the Newton–Raphson method, and return-mapping method were used. The tubes were meshed using four-node (Element with five points across the A was","PeriodicalId":103650,"journal":{"name":"Numerical Simulations in Engineering and Science","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134165717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：