Simulation of viscous flows with boundary layers within multiscale model using generalized hydrodynamics equations (مقاله لاتین

اختصاصی از فی بوو Simulation of viscous flows with boundary layers within multiscale model using generalized hydrodynamics equations (مقاله لاتین می باشد و فاقد ترجمه می باشد7ص ) دانلود با لینک مستقیم و پر سرعت .

Abstract
The multiscale method for computational fluid dynamics (CFD) is proposed to solve viscous flow problems at high Reynolds numbers with a thin boundary layer. This method is a physics-based model, uses generalized hydrodynamic equations proposed by Alexeev (1994), and can be interpreted as a regularization of the Navier-Stokes equations. Numerical solutions using this approach compare favorably with experimental data for the cases we considered for different flow problems in the range of Reynolds number from Re = 3200 to 1,000,000. The method is discussed and numerical solutions are compared with the experimental data for a 3D driven cavity flow at Re = 3200 and 10,000, 2D backward facing step flow at Re = 44,000, 2D channel flow at Re number up to 106, and a 3D thermal convection in a cylinder at Ra = 1000 to 150,000. Comparison with the analytical asymptotic solution is provided for a thermal convection, in the electrically conducting fluid suppressed by a strong magnetic field at Hartman numbers Ha up to 20,000. This multiphysics model is not a turbulence model, and no additional equations are introduced. Kinetic effects (small flow scales) are successfully captured with new terms introduced into the governing equations, and the derived small scale of turbulence compares well with observed in the experiments by Koseff and Street (1984).

ترجمه ماشینی

چکیده
روش چند مقیاسی برای دینامیک سیالات محاسباتی (CFD) ارائه شده است برای حل مشکلات جریان چسبناک در اعداد رینولدز بالا با لایه مرزی نازک. این روش یک مدل مبتنی بر فیزیک است، با استفاده از معادلات هیدرودینامیک عمومی پیشنهاد شده توسط Alexeev (1994)، و می تواند به عنوان یک تنظیم از معادلات ناویه استوکس تفسیر شده است. راه حل عددی استفاده از این روش مقایسه مطلوب با داده های تجربی برای موارد ما برای مشکلات جریان های مختلف در طیف وسیعی از عدد رینولدز از 3200 پاسخ = 1،000،000 نظر گرفته شود. این روش مورد بحث و راه حل های عددی در مقایسه با داده های تجربی برای 3D رانده جریان حفره در = 3200 و 10000 پاسخ، 2D به عقب مواجه جریان گام در = 44000، جریان کانال 2D در شماره پاسخ به 106 RE و 3D حرارتی همرفت در یک سیلندر در رادیوم = 1000 به 150.000. مقایسه با راه حل های مجانبی تحلیلی است که برای انتقال گرما ارائه شده، در مایع رسانا توسط یک میدان مغناطیسی قوی در اعداد هارتمن هکتار سرکوب تا 20،000. این مدل multiphysics است مدل مغشوش نیست، و هیچ معادلات اضافی معرفی شده است. اثرات جنبشی (مقیاس جریان کوچک) با موفقیت با شرایط جدید معرفی به معادلات حاکم دستگیر و در مقیاس کوچک مشتق شده از تلاطم خوبی مقایسه با مشاهده شده در آزمایش های Koseff و خیابان (1984).

دانلود مقاله Wire drawing process simulation of Polycrystalline diamond wire drawing die

اختصاصی از فی بوو دانلود مقاله Wire drawing process simulation of Polycrystalline diamond wire drawing die دانلود با لینک مستقیم و پر سرعت .

تعداد صفحات : 5

مشخصات :

Print ISBN:978-1-4673-0088-9

INSPEC Accession Number:12947178

DEM simulation of Centrifugal fertilizer (پایان نامه 200 ص به زبان انگلیسی )

اختصاصی از فی بوو DEM simulation of Centrifugal fertilizer (پایان نامه 200 ص به زبان انگلیسی ) دانلود با لینک مستقیم و پر سرعت .

List of contents
1 General introduction..............................................................................................................1
1.1 World fertilizer production and needs..............................................................................1
1.2 Centrifugal spreading in agriculture.................................................................................1
1.3 Need for spreader modelling ............................................................................................3
1.4 Existing spreader models .................................................................................................3
1.5 Introduction DEM in agriculture......................................................................................4
1.6 Objectives of the research ................................................................................................5
1.7 Outline of the research .....................................................................................................6
2 The Discrete Element Method...............................................................................................7
2.1 Introduction ......................................................................................................................7
2.2 DEM Algorithm flow .......................................................................................................8
2.3 Model parameter settings .................................................................................................9
2.4 Initializing the simulation.................................................................................................9
2.5 Contact resolution ..........................................................................................................11
2.5.1 Introduction ............................................................................................................11
2.5.2 Sphere-sphere contact ............................................................................................11
2.5.3 Sphere-rectangle contact ........................................................................................12
2.5.4 Sphere-cylinder contact..........................................................................................13
2.5.5 Sphere-disc contact ................................................................................................14
2.5.6 Contact with edges .................................................................................................16
2.6 Search algorithms...........................................................................................................18
2.7 Force calculation in DEM simulations...........................................................................19
2.7.1 Introduction ............................................................................................................19
2.8 Normal contact force models .........................................................................................22
2.8.1 Introduction ............................................................................................................22
2.8.2 The Kelvin–Voight model......................................................................................23
2.8.3 The Kono-Kuwabara model ...................................................................................23
2.8.4 Other normal contact models .................................................................................26
2.9 Tangential contact forces ...............................................................................................26
2.9.1 Introduction ............................................................................................................26
2.9.2 Linear model implementation ................................................................................27
2.10 Moments of forces..........................................................................................................29
2.11 Body Forces....................................................................................................................30
2.11.1 Aero dynamical drag force.....................................................................................30
2.11.2 Magnus effect.........................................................................................................31
2.12 Time integration algorithms ...........................................................................................31
2.12.1 Introduction ............................................................................................................31
2.12.2 Integration of Newton’s second law.......................................................................32
2.12.3 Euler method ..........................................................................................................32
2.12.4 Leapfrog method ....................................................................................................33
List of contents viii
2.12.5 Other integrators.....................................................................................................33
2.12.6 Choice of the time step...........................................................................................34
2.12.7 Integration of Euler’s law.......................................................................................35
2.12.8 Leapfrog integration...............................................................................................38
2.12.9 Integration errors ....................................................................................................38
2.13 Program overview ..........................................................................................................40
2.14 Conclusions ....................................................................................................................40
3 Particle measuring methods as input for numerical models............................................42
3.1 Introduction ....................................................................................................................42
3.2 Particle mass ( p m ) ........................................................................................................43
3.3 Particle radius ( p R ) and shape .......................................................................................43
3.3.1 Manual procedure...................................................................................................43
3.3.2 Automatic procedure ..............................................................................................44
3.3.3 Particle shape approximation .................................................................................45
3.3.4 Surface roughness ..................................................................................................50
3.4 Particle density (ρ ) p .....................................................................................................52
3.5 Particle stiffness (k ) ....................................................................................................52
3.5.1 Stiffness for sphere-sphere indenting.....................................................................53
3.5.2 Stiffness for sphere-cylinder indenting ..................................................................53
3.6 Particle damping coefficient (c) and restitution coefficient (e) ..................................54
3.6.1 Sphere-sphere damping ..........................................................................................58
3.7 Particle fracture resistance ( ) max N ................................................................................58
3.7.1 Impact with vanes and vane edges .........................................................................61
3.7.2 Static pressure in the bin ........................................................................................62
3.8 Particle friction coefficient (μ ) .....................................................................................62
3.8.1 Wall-particle friction ( wp μ ) ...................................................................................63
3.8.2 Particle-particle friction ( pp μ )................................................................................64
3.8.3 Static friction ..........................................................................................................65
3.9 Particle Aerodynamical drag coefficient ( d C ) ...............................................................65
3.10 Errors of the measurement methods...............................................................................66
3.11 Conclusions ....................................................................................................................67
4 Single particle simulations...................................................................................................68
4.1 Introduction ....................................................................................................................68
4.2 Comparison with analytical models ...............................................................................68
4.2.1 The rolling and friction force .................................................................................68
4.2.2 The centrifugal force ..............................................................................................71
4.2.3 The Coriolis force...................................................................................................73
4.3 Experimental methods....................................................................................................74
4.4 Experimental verification of single particle trajectories ................................................75
4.5 Analysis of the rotational motion in single particle trajectories.....................................79
4.6 Analysis of bouncing in single particle trajectories .......................................................83
4.7 Non - spherical particle simulations...............................................................................86
List of contents ix
4.8 Conclusions ....................................................................................................................88
5 Multi particle simulations....................................................................................................89
5.1 Introduction ....................................................................................................................89
5.2 Materials and methods ...................................................................................................90
5.2.1 Introduction ............................................................................................................90
5.2.2 Cylindrical measurements ......................................................................................90
5.2.3 Rectangular measurements (TSP) ..........................................................................91
5.2.4 Fertilizer choice and property measurements.........................................................93
5.2.5 Choice of disc type and bin ....................................................................................96
5.3 Computational setup.......................................................................................................99
5.3.1 Introduction ............................................................................................................99
5.3.2 Initial conditions in the bin...................................................................................100
5.3.3 Spinning disc simulations.....................................................................................103
5.3.4 Ballistic model......................................................................................................104
5.3.5 Model output variables.........................................................................................104
5.3.6 Characterisation time of the simulated pattern.....................................................104
5.3.7 Sensitivity to bin filling........................................................................................105
5.4 Results and discussion..................................................................................................105
5.4.1 Cylindrical spread pattern measurements ............................................................105
5.4.2 TSP measurements ...............................................................................................111
5.5 Conclusions of the experiments ...................................................................................118
6 Model parameter sensitivity..............................................................................................120
6.1 Introduction ..................................................................................................................120
6.2 Definition of sensitivity................................................................................................120
6.3 Influence of friction coefficient....................................................................................123
6.3.1 Particle-wall friction.............................................................................................123
6.3.2 Particle-particle friction........................................................................................128
6.3.3 Conclusion on friction coefficients ......................................................................129
6.4 Influence of elasticity and damping .............................................................................130
6.4.1 Influence of particle stiffness ...............................................................................130
6.5 Influence of bulk flow ..................................................................................................132
6.5.1 Flow rate...............................................................................................................133
6.5.2 Influence of orifice shape.....................................................................................134
6.6 Influence of particle diameter and segregation ............................................................136
6.6.1 Particle diameter...................................................................................................136
6.6.2 Segregation...........................................................................................................140
6.7 Influence of particle shape ...........................................................................................141
6.7.1 Introduction ..........................................................................................................141
6.7.2 Results ..................................................................................................................143
6.8 External forces..............................................................................................................146
6.9 Interaction of parameters..............................................................................................147
6.9.1 Friction - particle shape........................................................................................148
6.9.2 Friction - bulk flow rate .......................................................................................149
6.9.3 Bulk flow segregation ..........................................................................................149
6.9.4 Friction – working width......................................................................................151
6.10 Particle interception......................................................................................................151
6.11 Discussion on sensitivity...........................................................................................152
List of contents x
6.12 Conclusions ..................................................................................................................159
7 Case study: DEM simulations of a new concept for lawn spreaders.............................161
7.1 Introduction ..................................................................................................................161
7.2 Situation and current technology..................................................................................161
7.3 Design of the new concept ...........................................................................................162
7.4 Flow rate regulation of the pocket system ...................................................................163
7.5 DEM simulations..........................................................................................................166
7.5.1 Introduction ..........................................................................................................166
7.5.2 Simulation of ideal conditions, current technology .............................................167
7.5.3 Simulation of modified conditions.......................................................................168
7.6 Conclusions ..................................................................................................................170
8 General conclusions and future outline............................................................................171
8.1 General conclusions .....................................................................................................171
8.2 Suggestions for future work .........................................................................................174
9 Bibliography .......................................................................................................................177

آموزش تصویری Simulation and Analysis سالید ورکس

اختصاصی از فی بوو آموزش تصویری Simulation and Analysis سالید ورکس دانلود با لینک مستقیم و پر سرعت .

Reservoir Quality Modeling and Streamline Simulation: An Application in Campos Basin, Brazil

اختصاصی از فی بوو Reservoir Quality Modeling and Streamline Simulation: An Application in Campos Basin, Brazil دانلود با لینک مستقیم و پر سرعت .

مقاله SPE 71353