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Flow velocity

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The flow velocity of a fluid effectively describes everything about the motion of a fluid. Many physical properties of a fluid can be expressed mathematically in terms of the flow velocity. Some common examples follow:
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Duderstadt, James J.; Martin, William R. (1979). "Chapter 4:The derivation of continuum description from transport equations". In Wiley-Interscience Publications (ed.).
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Freidberg, Jeffrey P. (2008). "Chapter 10:A self-consistent two-fluid model". In Cambridge University Press (ed.).
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Vector field which is used to mathematically describe the motion of a continuum
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is not known in every point and the only accessible velocity is the
159: 351:{\displaystyle {\frac {\partial \mathbf {u} }{\partial t}}=0.} 715:, of a flow can be defined in terms of its flow velocity by 148:{\displaystyle \mathbf {u} =\mathbf {u} (\mathbf {x} ,t),} 877:
In many engineering applications the local flow velocity
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If the flow is both irrotational and incompressible, the
66:. The length of the flow velocity vector is scalar, the 1167: 999: 976: 947: 915: 883: 847: 831:{\displaystyle \mathbf {u} =\nabla \mathbf {\phi } .} 808: 785: 724: 701: 655: 617: 594: 554: 517: 492: 444: 407: 382: 319: 294: 230: 197: 174: 111: 758:
If the vorticity is zero, the flow is irrotational.
748:{\displaystyle \omega =\nabla \times \mathbf {u} .} 1034: 982: 962: 930: 891: 853: 830: 791: 747: 707: 670: 637: 603: 562: 537: 500: 452: 427: 390: 350: 302: 250: 207: 183: 147: 1206: 1251: 1035:{\displaystyle {\bar {u}}={\frac {\dot {V}}{A}}} 62:used to mathematically describe the motion of a 538:{\displaystyle \nabla \times \mathbf {u} =0.} 581:which is irrotational can be described as a 428:{\displaystyle \nabla \cdot \mathbf {u} =0.} 245: 237: 1192:: CS1 maint: location missing publisher ( 1153:: CS1 maint: location missing publisher ( 638:{\displaystyle \mathbf {u} =\nabla \Phi .} 221:is the length of the flow velocity vector 761: 204: 180: 649:of the velocity potential must be zero: 14: 1252: 1172:(1 ed.). Cambridge. p. 225. 361: 310:does not vary with time. That is if 467: 990:(with dimension of square length): 772:If an irrotational flow occupies a 24: 817: 731: 659: 656: 629: 626: 595: 518: 408: 333: 323: 284:The flow of a fluid is said to be 251:{\displaystyle q=\|\mathbf {u} \|} 25: 1296: 776:fluid region then there exists a 372:If a fluid is incompressible the 1170:Plasma Physics and Fusion Energy 885: 872: 810: 738: 619: 556: 525: 494: 446: 415: 384: 327: 296: 241: 176: 129: 121: 113: 1217:Supersonic Flow and Shock Waves 671:{\displaystyle \Delta \Phi =0.} 1200: 1161: 1122: 1054:Displacement field (mechanics) 1006: 922: 273: 184:{\displaystyle \mathbf {x} \,} 139: 125: 13: 1: 1115: 102:of a fluid is a vector field 91: 892:{\displaystyle \mathbf {u} } 680: 563:{\displaystyle \mathbf {u} } 501:{\displaystyle \mathbf {u} } 453:{\displaystyle \mathbf {u} } 391:{\displaystyle \mathbf {u} } 303:{\displaystyle \mathbf {u} } 7: 1046: 10: 1301: 1285:Vector physical quantities 963:{\displaystyle {\dot {V}}} 931:{\displaystyle {\bar {u}}} 765: 684: 471: 365: 277: 1133:. New York. p. 218. 867:Irrotational vector field 572:irrotational vector field 76:; when evaluated along a 708:{\displaystyle \omega } 585:, through the use of a 579:simply-connected domain 462:solenoidal vector field 264: 261:and is a scalar field. 1036: 984: 964: 932: 893: 855: 832: 793: 762:The velocity potential 749: 709: 672: 639: 605: 604:{\displaystyle \Phi ,} 564: 539: 502: 454: 429: 392: 352: 304: 252: 209: 185: 149: 1037: 985: 965: 933: 908:average flow velocity 894: 856: 854:{\displaystyle \phi } 833: 794: 792:{\displaystyle \phi } 750: 710: 673: 640: 606: 565: 540: 503: 455: 430: 393: 353: 305: 253: 210: 186: 150: 48:statistical mechanics 997: 974: 945: 913: 881: 845: 806: 783: 722: 699: 653: 615: 592: 552: 515: 490: 442: 405: 380: 317: 292: 228: 208:{\displaystyle t.\,} 195: 172: 109: 72:. It is also called 44:macroscopic velocity 1265:Continuum mechanics 865:for the flow. (See 368:Incompressible flow 362:Incompressible flow 32:continuum mechanics 1099:Velocity potential 1089:Strain-rate tensor 1032: 980: 960: 928: 889: 863:velocity potential 851: 828: 789: 745: 705: 668: 635: 601: 587:velocity potential 560: 535: 498: 450: 425: 388: 348: 300: 248: 205: 181: 145: 96:The flow velocity 1079:Pressure gradient 1074:Particle velocity 1030: 1025: 1009: 983:{\displaystyle A} 957: 925: 841:The scalar field 474:Irrotational flow 468:Irrotational flow 340: 80:, it is called a 16:(Redirected from 1292: 1280:Spatial gradient 1244: 1243: 1212:Friedrichs, K.O. 1204: 1198: 1197: 1191: 1183: 1165: 1159: 1158: 1152: 1144: 1131:Transport theory 1126: 1041: 1039: 1038: 1033: 1031: 1026: 1018: 1016: 1011: 1010: 1002: 989: 987: 986: 981: 969: 967: 966: 961: 959: 958: 950: 940:volume flow rate 937: 935: 934: 929: 927: 926: 918: 898: 896: 895: 890: 888: 860: 858: 857: 852: 837: 835: 834: 829: 824: 813: 798: 796: 795: 790: 774:simply-connected 754: 752: 751: 746: 741: 714: 712: 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549: 524: 516: 513: 512: 493: 491: 488: 487: 476: 470: 445: 443: 440: 439: 414: 406: 403: 402: 383: 381: 378: 377: 370: 364: 332: 326: 322: 320: 318: 315: 314: 295: 293: 290: 289: 282: 276: 267: 240: 229: 226: 225: 217:The flow speed 196: 193: 192: 175: 173: 170: 169: 128: 120: 112: 110: 107: 106: 94: 86:law of the wall 28: 23: 22: 15: 12: 11: 5: 1298: 1288: 1287: 1282: 1277: 1272: 1267: 1262: 1260:Fluid dynamics 1246: 1245: 1230: 1199: 1179:978-0521733175 1178: 1160: 1140:978-0471044925 1139: 1120: 1119: 1117: 1114: 1112: 1111: 1106: 1101: 1096: 1091: 1086: 1081: 1076: 1071: 1069:Group velocity 1066: 1061: 1059:Drift velocity 1056: 1050: 1048: 1045: 1044: 1043: 1029: 1024: 1021: 1014: 1008: 1005: 979: 956: 953: 924: 921: 887: 874: 871: 861:is called the 850: 839: 838: 827: 823: 819: 816: 812: 788: 768:Potential flow 766:Main article: 763: 760: 756: 755: 744: 740: 736: 733: 730: 727: 704: 685:Main article: 682: 679: 667: 664: 661: 658: 634: 631: 628: 625: 621: 600: 597: 583:potential flow 558: 546: 545: 534: 531: 527: 523: 520: 496: 472:Main article: 469: 466: 448: 436: 435: 424: 421: 417: 413: 410: 386: 366:Main article: 363: 360: 359: 358: 347: 344: 338: 335: 329: 325: 298: 278:Main article: 275: 272: 266: 263: 259: 258: 247: 243: 239: 236: 233: 203: 200: 178: 168:at a position 156: 155: 144: 141: 138: 135: 131: 127: 123: 119: 115: 93: 90: 84:(as in, e.g., 74:velocity field 52:drift velocity 40:fluid dynamics 26: 18:Fluid velocity 9: 6: 4: 3: 2: 1297: 1286: 1283: 1281: 1278: 1276: 1273: 1271: 1268: 1266: 1263: 1261: 1258: 1257: 1255: 1241: 1237: 1233: 1227: 1223: 1219: 1218: 1213: 1209: 1203: 1195: 1189: 1181: 1175: 1171: 1164: 1156: 1150: 1142: 1136: 1132: 1125: 1121: 1110: 1109:Wind velocity 1107: 1105: 1102: 1100: 1097: 1095: 1092: 1090: 1087: 1085: 1082: 1080: 1077: 1075: 1072: 1070: 1067: 1065: 1062: 1060: 1057: 1055: 1052: 1051: 1027: 1022: 1019: 1012: 1003: 993: 992: 991: 977: 954: 951: 941: 919: 909: 905: 904:bulk velocity 901: 873:Bulk velocity 870: 868: 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1214:(1999) . 1188:cite book 1149:cite book 1104:Vorticity 1064:Enstrophy 1023:˙ 1007:¯ 955:˙ 923:¯ 849:ϕ 822:ϕ 818:∇ 787:ϕ 735:× 732:∇ 726:ω 703:ω 693:vorticity 687:Vorticity 681:Vorticity 660:Φ 657:Δ 647:Laplacian 630:Φ 627:∇ 596:Φ 522:× 519:∇ 508:is zero: 412:⋅ 409:∇ 398:is zero: 334:∂ 324:∂ 246:‖ 238:‖ 191:and time 64:continuum 1275:Velocity 1240:44071435 1047:See also 160:velocity 482:if the 58:, is a 42:, also 1238:  1228:  1176:  1137:  570:is an 286:steady 162:of an 611:with 460:is a 50:, or 1236:OCLC 1226:ISBN 1194:link 1174:ISBN 1155:link 1135:ISBN 691:The 484:curl 265:Uses 78:line 34:the 906:or 869:.) 486:of 376:of 288:if 88:). 54:in 46:in 38:in 30:In 1256:: 1234:. 1224:. 1222:24 1210:; 1190:}} 1186:{{ 1151:}} 1147:{{ 695:, 666:0. 574:. 533:0. 464:. 423:0. 346:0. 1242:. 1196:) 1182:. 1157:) 1143:. 1042:. 1028:A 1020:V 1013:= 1004:u 978:A 952:V 920:u 886:u 826:. 815:= 811:u 743:. 739:u 729:= 663:= 633:. 624:= 620:u 599:, 557:u 530:= 526:u 495:u 447:u 420:= 416:u 385:u 343:= 337:t 328:u 297:u 242:u 235:= 232:q 219:q 202:. 199:t 177:x 143:, 140:) 137:t 134:, 130:x 126:( 122:u 118:= 114:u 99:u 20:)

Index

Fluid velocity
continuum mechanics
fluid dynamics
statistical mechanics
electromagnetism
vector field
continuum
line
law of the wall
velocity
element of fluid
Steady flow
Incompressible flow
divergence
solenoidal vector field
Irrotational flow
curl
irrotational vector field
simply-connected domain
potential flow
velocity potential
Laplacian
Vorticity
Potential flow
simply-connected
scalar field
velocity potential
Irrotational vector field
vector field
volume flow rate

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