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esults of the data to which it was fitted but no other data was presented. A later paper, Elghobashi et al (1984) , used the model to simulate a similar jet with different sized particles and found agreement with experiment to within 8% for the particle velocity for this similar flow geometry- 3 LAGRANGIAN PARTICLE MODELLING Berlemont et al (1990) used a second order k-e closure scheme in a two-fluid simulation. The dispersed phase was tracked in a Lagrangian trajectory approach, wherein a number of trajectories were simulated in a given turbulence field and then reassembled statistically to give the particle dispersion rates. Their main assumption was that the turbulence was homogenous, so when the model was validated by comparison with grid generated turbulence and pipe flow the results compared well with experiment. When particle-laden jet flows were predicted and compared with experiments the errors were of order 200% in some areas of the flow. While fluid RMS velocities agreed well a wide disparity existed between experimental and calculated particle velocities. A5-3
APPENDIX 6: K-e MODEL OF JOHNS ET AL (1990) The horizontal and vertical equations of motion and the continuity equation used by Johns et al (1990) were , , dt dx oz p dx dt dx dz p dz dx dz where p was the liquid density (viscous stresses were omitted in this equation) . Combining the continuity and vertical equations gave dw + d(uw) + d(w 2 ) __ _J1 _5p /2\ dt dx dz p dz which was integrated from an arbitrary depth to the free surface with boundary condition p=p a (ie constant atmospheric pressure) at z=£. The kinematic condition at the free surface gave w = , at z=C (3) and then vertical integration gave f C dtJ """ dxJ ""•'" (4) Reynolds averaging and substitution, neglecting turbulent departures in f gave A6-1
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FLUID-PARTICLE TRANSPORT DYNAMICS O
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SYNOPSIS The local dynamics of sand
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TABLE OF CONTENTS LIST OF FIGURES C
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CHAPTER 3: JETTING EXPERIMENTS Summ
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2 Numerical scheme 6-5 3 Results 6-
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LIST OF FIGURES Chapter 1 Figure 1.
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U=830mm/s. Figure 16. Thomas et al
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in the boundary layer. a) The forma
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Chapter 3 Figure 1. After Alien (19
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at various values of U/V from 2.7 t
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y Coanda-flapping of the free shear
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of a sandwave crest in the estuary
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Figure 7h-i. The temporal fluctuati
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inclined downwards whereas the time
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starting position (X,Y) at zero ini
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d Sand grain diameter (m) Fi Number
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G Vortex core growth rate (tn/s) ki
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1 INTRODUCTION Sand forms the botto
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where U is the depth-averaged veloc
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The wavelengths of dunes primarily
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detached and then confined within a
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The vortex radius rn and apparent w
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Recent work by Nezu & Nakagawa (199
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found in the outer streaks. 4 MODEL
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(1987), for example, modelled gas-s
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Profiles of shear stress and turbul
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6ft v "' ' Re In the limit of large
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that the particle radius was much s
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and travels downstream at speed }*U
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capture by transient large eddies s
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Chapter 1 Figure 3. Alien (1984). L
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Chapter 1 10 8 e 4 I 08 •- 02 Yal
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Chapter 1 bw speed fluid Figure 11.
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Chapter 1 Figure 16. Thomas et al (
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Chapter 1 StCMl STRESS SCALE « K /
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Chapter 1 Haiht Vdodty Figure 22. S
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Chapter 1 Time = 1.2 2.4 ' ' :•
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1 INTRODUCTION AND DESIGN CONSIDERA
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Initial costing for a flume of the
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flanges and a maximum flow rate of
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could be wound above or below the l
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4 EXPERIMENTAL SETUP AND METHODS He
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4.2 Flow visualisation and model pa
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any divergence from the beam and to
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even flow over 0.45m width and up t
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Chapter 2 Opt 1 h(m) 0.01 Max D(m)
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Chapter 2 Part of side section Putt
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Chapter 2 Suction tank Bypass Disch
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Chapter 2 QUncorrectedflow £ Corre
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Chapter 2 60 r 501 40? 30r 20 r lOr
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1_ INTRODUCTION The main features o
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2 EXPERIMENTAL METHODS A detailed d
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the relationship is then simply ^ -
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number about 0.14. They were taken
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along the stoss slope. Figures 8 an
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3.3a) Jetting trajectories when U/V
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errors increase substantially due t
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likely distributions. 4 DISCUSSION
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Our suggestion here is akin to that
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not accommodate the differing migra
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considered by proponents of numeric
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Chapter 3 C,;: Figure 3a-j. The pla
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Q CO 23 Figure 6. Distribution of p
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Chapter 3 X(cm) 1 2 3 4 5 6 7 8 9 1
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Chapter 3 U(m/s) V(m/s) U/V M1+M2 M
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O I r+ 21 CO 2 5 8 11 14 17 20 23 >
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8 11 14 17 20 23 25 + Position Figu
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Chapter 3 U/V= B5.7 Q9.3 BlO.7^12.8
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Chapter 3 Band 1 2 3 4 U(m/s) 0.2 0
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1 INTRODUCTION In chapter 3 we cons
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velocity for a maximum of 40% of th
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layer vortices extending over the d
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2.2 Methods for measuring Coanda-fl
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Section 3.4 considers suspension fr
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This same flow structure has also b
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3.2b) Effect of varying inter-crest
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those with fall speed 0.060m/s for
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3.4 Particle capture from stoss slo
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are discussed in the context of est
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jetted grains settling to the lee s
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Chapter 4 ENTRAINED FLOW Figure 1.
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Figure 3a-j. The plates show partic
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Chapter 4 Percentage occurrence •
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Chapter 4 Interval (s) 60 80 100 12
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Chapter 4 0.024m Conc=8% Figure 12.
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Chapter 4 Figure 16. A cloud of par
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1 INTRODUCTION We use a Rankine vor
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effective particle fall speed in th
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particle velocity Vx=0. The initial
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the vortex axis. Vortex circulation
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dimensional fall times T^ for diffe
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horizontal component lift force (fi
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corresponds to the trajectory trave
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stepping the calculation in VT . Do
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averaged exclusion of the coherent
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C from figure 11 (ie 2.2) then we h
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PflRTICLE DENSITY=1000.000 Kg/n3 LI
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Chapter 5 ft) J k I Figure 4. Varyi
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Chapter 5 Relative Fall Time va Sta
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Chapter 5 Figure 7a. Trajectories o
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Chapter 5 Velocity X —Inertia X L
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Chapter 5 Velocity X —Velocity Y
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Chapter 5 Velocity Y Inertia Y Lift
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Chapter 5 DENSITY PARTICLE=2850.000
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Chapter 5 Rad = 0.006 Rad=0.003 Rad
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Chapter 5 H3 Y=0 Oy=i m Y=2 D-y=3
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CHAPTER 6: NUMERICAL SIMULATION OF
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next. If we now adopt the classical
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st = (4) Where p p was the particle
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3 RESULTS 3.1 Specified 6 and V Fig
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the blue squares to double loops an
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A0fl0 = 1.25V-0.33G-0.005 (7) and f
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Conversely, the upper line of the p
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equations. Such a discrete vortex m
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Figure 1. Schematic of the shear la
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Chapter 6 J G H K M Figure 3. Seven
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Chapter 6 1 T V=0.161 0.1 -- V41185
Page 235 and 236: Chapter 6 - DataV=0.0335, G=0.01
Page 237 and 238: CHAPTER 7: RECAPITULATION AND RECOM
Page 239 and 240: were shown to compare well with pre
Page 241 and 242: We have shown Coanda-flapping makes
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Page 247 and 248: Figure la-g. The seven trajectory m
Page 249 and 250: Chapter 7
Page 251 and 252: Chapter 7 0.0351 0.03 " 03 0.025 0.
Page 253 and 254: Flow 16 (1) pp 19-34. Bernal LP (19
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Page 261 and 262: Spalding (1961). A single formula f
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Page 265 and 266: APPENDIX 1: BOUNDARY LAYER STUDIES
Page 267 and 268: (1967) used hydrogen bubble visuali
Page 269 and 270: The burst-sweep dynamics study of U
Page 271 and 272: Horseshoe vortex Vortex filament Ho
Page 273 and 274: APPENDIX 2: FAST9003.HR(RW)/NHT - P
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Page 277 and 278: transport dynamics of multiphase fl
Page 279 and 280: APPENDIX 3: FUNDAMENTAL NAVIER-STOK
Page 281 and 282: APPENDIX 4: CLOSURE METHODS 1 ZERO
Page 283 and 284: where cr k and CD are empirical con
Page 285: K = CDe^ 2 p 2 \U2 -U1 \=e 1e 2 c (
Page 289 and 290: They then defined a hydrodynamic co
Page 291 and 292: with respect to the rest of the vor
Page 293 and 294: The vorticity equation can be split
Page 295 and 296: around the crest and the motion of
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Page 299 and 300: i——COMPARISON WITH PREVIOUS WOR
Page 301 and 302: width speed (metres) ^(cm/s) 11 Fig
Page 303 and 304: U (33) = 1.16ms-' Depth = 2.65 m Fi
Page 305 and 306: APPENDIX 9 : DERIVATION OF FORCES O
Page 307 and 308: APPENDIX 10 : MODEL CODE FOR CALCUL
Page 309 and 310: APPENDIX 11: MODEL CODE FOR GROWING
Page 311: 105 if (scancode .eq. 57) stop GOTO
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