Knowledge (XXG)

Taylor–Goldstein equation

Source 📝

95: 727: 1053: 511: 102:
diagram of the base state of the system. The flow under investigation represents a small perturbation away from this state. While the base state is parallel, the perturbation velocity has components in both
404: 519: 942: 772: 284: 334: 160: 935: 899: 850: 823: 800: 133: 417: 1152: 775: 86:, who derived the equation independently from each other in 1931. The third independent derivation, also in 1931, was made by B. Haurwitz. 1142: 72: 1124: 1081: 44: 68: 853: 722:{\displaystyle (U-c)^{2}\left({d^{2}{\tilde {\phi }} \over dz^{2}}-\alpha ^{2}{\tilde {\phi }}\right)+\left{\tilde {\phi }}=0,} 343: 24: 1147: 1048:{\displaystyle \alpha {\tilde {\phi }}={d{\tilde {\phi }} \over dz}=0\quad {\text{ at }}z=z_{1}{\text{ and }}z=z_{2}.} 112: 735: 28: 825:
is positive, then the flow is unstable, and the small perturbation introduced to the system is amplified in time.
1157: 168: 79: 60: 1162: 40: 292: 138: 1167: 1120: 1077: 904: 865: 871: 829: 83: 513:
for the flow, the following dimensional form of the Taylor–Goldstein equation is obtained:
36: 835: 808: 803: 785: 411: 118: 56: 32: 1136: 52: 779: 64: 852:
results in a flow which is always unstable. This instability is known as the
506:{\displaystyle u_{x}'=d{\tilde {\phi }}/dz,u_{z}'=-i\alpha {\tilde {\phi }}} 407: 99: 94: 48: 336:
is the unperturbed or basic flow. The perturbation velocity has the
108: 93: 16:
Ordinary differential equation used in the field of fluid dynamics
337: 51:
forces (e.g. gravity), for stably stratified fluids in the
399:{\displaystyle \mathbf {u} '\propto \exp(i\alpha (x-ct))} 67:. The Taylor–Goldstein equation is derived from the 2D 945: 907: 874: 864:
The relevant boundary conditions are, in case of the
838: 811: 788: 738: 522: 420: 346: 295: 171: 141: 121: 1047: 929: 893: 868:boundary conditions at the channel top and bottom 844: 817: 794: 766: 721: 505: 398: 328: 278: 154: 135:and a mean density gradient (with gradient-length 127: 1094: 1092: 767:{\displaystyle N={\sqrt {g \over L_{\rho }}}} 410:understood). Using this knowledge, and the 8: 1036: 1021: 1015: 1000: 971: 970: 964: 950: 949: 944: 918: 906: 885: 873: 837: 810: 787: 755: 745: 737: 699: 698: 684: 666: 659: 635: 607: 606: 600: 584: 564: 563: 557: 550: 539: 521: 492: 491: 470: 452: 441: 440: 425: 419: 348: 345: 294: 275: 172: 170: 146: 140: 120: 1064: 162:), for the perturbation velocity field 55:. Or, more generally, the dynamics of 1098: 279:{\displaystyle \mathbf {u} =\left,\,} 107:The equation is derived by solving a 7: 59:in the presence of a (continuous) 14: 1117:Wave interactions and fluid flows 349: 173: 999: 802:. If the imaginary part of the 1119:, Cambridge University Press, 976: 955: 704: 656: 644: 612: 569: 536: 523: 497: 446: 393: 390: 375: 366: 323: 308: 302: 296: 264: 246: 226: 208: 194: 188: 25:ordinary differential equation 1: 1076:, New York: Academic Press, 782:parameter of the problem is 78:The equation is named after 45:Kelvin–Helmholtz instability 1153:Equations of fluid dynamics 860:No-slip boundary conditions 854:Rayleigh–Taylor instability 1184: 1143:Atmospheric thermodynamics 329:{\displaystyle (U(z),0,0)} 29:geophysical fluid dynamics 155:{\displaystyle L_{\rho }} 115:, in presence of gravity 21:Taylor–Goldstein equation 930:{\displaystyle z=z_{2}:} 832:Brunt–Väisälä frequency 73:Boussinesq approximation 39:flows. It describes the 31:, and more generally in 894:{\displaystyle z=z_{1}} 776:Brunt–Väisälä frequency 35:, in presence of quasi- 1115:Craik, A.D.D. (1988), 1049: 931: 895: 846: 819: 796: 768: 723: 507: 400: 330: 280: 156: 129: 113:Navier–Stokes equation 104: 61:density stratification 53:dissipation-less limit 27:used in the fields of 1050: 932: 896: 847: 820: 797: 769: 724: 508: 401: 331: 281: 157: 130: 97: 1148:Atmospheric dynamics 1072:Kundu, P.J. (1990), 943: 905: 872: 836: 809: 786: 736: 520: 418: 344: 293: 169: 139: 119: 478: 433: 1045: 927: 891: 842: 815: 792: 764: 719: 503: 466: 421: 396: 326: 276: 152: 125: 105: 1101:, pp. 27–28) 1024: 1003: 991: 979: 958: 845:{\displaystyle N} 818:{\displaystyle c} 795:{\displaystyle c} 762: 761: 707: 691: 615: 591: 572: 500: 449: 128:{\displaystyle g} 1175: 1129: 1102: 1096: 1087: 1086: 1069: 1054: 1052: 1051: 1046: 1041: 1040: 1025: 1022: 1020: 1019: 1004: 1001: 992: 990: 982: 981: 980: 972: 965: 960: 959: 951: 936: 934: 933: 928: 923: 922: 900: 898: 897: 892: 890: 889: 851: 849: 848: 843: 830:purely imaginary 824: 822: 821: 816: 801: 799: 798: 793: 773: 771: 770: 765: 763: 760: 759: 747: 746: 728: 726: 725: 720: 709: 708: 700: 697: 693: 692: 690: 689: 688: 675: 671: 670: 660: 640: 639: 622: 618: 617: 616: 608: 605: 604: 592: 590: 589: 588: 575: 574: 573: 565: 562: 561: 551: 544: 543: 512: 510: 509: 504: 502: 501: 493: 474: 456: 451: 450: 442: 429: 405: 403: 402: 397: 356: 352: 335: 333: 332: 327: 285: 283: 282: 277: 271: 267: 245: 207: 176: 161: 159: 158: 153: 151: 150: 134: 132: 131: 126: 1183: 1182: 1178: 1177: 1176: 1174: 1173: 1172: 1133: 1132: 1127: 1114: 1111: 1106: 1105: 1097: 1090: 1084: 1074:Fluid Mechanics 1071: 1070: 1066: 1061: 1032: 1023: and  1011: 983: 966: 941: 940: 914: 903: 902: 881: 870: 869: 862: 834: 833: 807: 806: 784: 783: 751: 734: 733: 680: 676: 662: 661: 631: 630: 626: 596: 580: 576: 553: 552: 549: 545: 535: 518: 517: 416: 415: 414:representation 347: 342: 341: 340:-like solution 291: 290: 238: 200: 184: 180: 167: 166: 142: 137: 136: 117: 116: 111:version of the 92: 69:Euler equations 17: 12: 11: 5: 1181: 1179: 1171: 1170: 1165: 1160: 1158:Fluid dynamics 1155: 1150: 1145: 1135: 1134: 1131: 1130: 1125: 1110: 1107: 1104: 1103: 1088: 1082: 1063: 1062: 1060: 1057: 1056: 1055: 1044: 1039: 1035: 1031: 1028: 1018: 1014: 1010: 1007: 1002: at  998: 995: 989: 986: 978: 975: 969: 963: 957: 954: 948: 926: 921: 917: 913: 910: 888: 884: 880: 877: 861: 858: 841: 814: 791: 758: 754: 750: 744: 741: 730: 729: 718: 715: 712: 706: 703: 696: 687: 683: 679: 674: 669: 665: 658: 655: 652: 649: 646: 643: 638: 634: 629: 625: 621: 614: 611: 603: 599: 595: 587: 583: 579: 571: 568: 560: 556: 548: 542: 538: 534: 531: 528: 525: 499: 496: 490: 487: 484: 481: 477: 473: 469: 465: 462: 459: 455: 448: 445: 439: 436: 432: 428: 424: 412:streamfunction 395: 392: 389: 386: 383: 380: 377: 374: 371: 368: 365: 362: 359: 355: 351: 325: 322: 319: 316: 313: 310: 307: 304: 301: 298: 287: 286: 274: 270: 266: 263: 260: 257: 254: 251: 248: 244: 241: 237: 234: 231: 228: 225: 222: 219: 216: 213: 210: 206: 203: 199: 196: 193: 190: 187: 183: 179: 175: 149: 145: 124: 91: 88: 57:internal waves 33:fluid dynamics 15: 13: 10: 9: 6: 4: 3: 2: 1180: 1169: 1166: 1164: 1161: 1159: 1156: 1154: 1151: 1149: 1146: 1144: 1141: 1140: 1138: 1128: 1126:0-521-36829-4 1122: 1118: 1113: 1112: 1108: 1100: 1095: 1093: 1089: 1085: 1083:0-12-178253-0 1079: 1075: 1068: 1065: 1058: 1042: 1037: 1033: 1029: 1026: 1016: 1012: 1008: 1005: 996: 993: 987: 984: 973: 967: 961: 952: 946: 939: 938: 937: 924: 919: 915: 911: 908: 886: 882: 878: 875: 867: 859: 857: 855: 839: 831: 826: 812: 805: 789: 781: 777: 756: 752: 748: 742: 739: 716: 713: 710: 701: 694: 685: 681: 677: 672: 667: 663: 653: 650: 647: 641: 636: 632: 627: 623: 619: 609: 601: 597: 593: 585: 581: 577: 566: 558: 554: 546: 540: 532: 529: 526: 516: 515: 514: 494: 488: 485: 482: 479: 475: 471: 467: 463: 460: 457: 453: 443: 437: 434: 430: 426: 422: 413: 409: 387: 384: 381: 378: 372: 369: 363: 360: 357: 353: 339: 320: 317: 314: 311: 305: 299: 272: 268: 261: 258: 255: 252: 249: 242: 239: 235: 232: 229: 223: 220: 217: 214: 211: 204: 201: 197: 191: 185: 181: 177: 165: 164: 163: 147: 143: 122: 114: 110: 101: 96: 89: 87: 85: 81: 76: 74: 70: 66: 62: 58: 54: 50: 47:, subject to 46: 42: 38: 34: 30: 26: 22: 1163:Oceanography 1116: 1073: 1067: 863: 828:Note that a 827: 774:denotes the 731: 288: 106: 84:S. Goldstein 77: 71:, using the 20: 18: 1099:Craik (1988 103:directions. 90:Formulation 80:G.I. Taylor 1137:Categories 1109:References 804:wave speed 780:eigenvalue 109:linearized 65:shear flow 977:~ 974:ϕ 956:~ 953:ϕ 947:α 757:ρ 705:~ 702:ϕ 651:− 642:− 613:~ 610:ϕ 598:α 594:− 570:~ 567:ϕ 530:− 498:~ 495:ϕ 489:α 483:− 447:~ 444:ϕ 408:real part 382:− 373:α 364:⁡ 358:∝ 148:ρ 100:schematic 1168:Buoyancy 476:′ 431:′ 354:′ 243:′ 205:′ 49:buoyancy 41:dynamics 866:no-slip 43:of the 1123:  1080:  778:. The 732:where 289:where 23:is an 1059:Notes 1121:ISBN 1078:ISBN 901:and 338:wave 82:and 63:and 19:The 361:exp 1139:: 1091:^ 856:. 98:A 75:. 37:2D 1043:. 1038:2 1034:z 1030:= 1027:z 1017:1 1013:z 1009:= 1006:z 997:0 994:= 988:z 985:d 968:d 962:= 925:: 920:2 916:z 912:= 909:z 887:1 883:z 879:= 876:z 840:N 813:c 790:c 753:L 749:g 743:= 740:N 717:, 714:0 711:= 695:] 686:2 682:z 678:d 673:U 668:2 664:d 657:) 654:c 648:U 645:( 637:2 633:N 628:[ 624:+ 620:) 602:2 586:2 582:z 578:d 559:2 555:d 547:( 541:2 537:) 533:c 527:U 524:( 486:i 480:= 472:z 468:u 464:, 461:z 458:d 454:/ 438:d 435:= 427:x 423:u 406:( 394:) 391:) 388:t 385:c 379:x 376:( 370:i 367:( 350:u 324:) 321:0 318:, 315:0 312:, 309:) 306:z 303:( 300:U 297:( 273:, 269:] 265:) 262:t 259:, 256:z 253:, 250:x 247:( 240:w 236:, 233:0 230:, 227:) 224:t 221:, 218:z 215:, 212:x 209:( 202:u 198:+ 195:) 192:z 189:( 186:U 182:[ 178:= 174:u 144:L 123:g

Index

ordinary differential equation
geophysical fluid dynamics
fluid dynamics
2D
dynamics
Kelvin–Helmholtz instability
buoyancy
dissipation-less limit
internal waves
density stratification
shear flow
Euler equations
Boussinesq approximation
G.I. Taylor
S. Goldstein

schematic
linearized
Navier–Stokes equation
wave
real part
streamfunction
Brunt–Väisälä frequency
eigenvalue
wave speed
purely imaginary
Rayleigh–Taylor instability
no-slip
ISBN
0-12-178253-0

Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.