Changeset 10414 for NEMO/trunk/doc/latex/NEMO/subfiles/chap_LBC.tex
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NEMO/trunk/doc/latex/NEMO/subfiles/chap_LBC.tex
r10406 r10414 1 \documentclass[../tex_main/NEMO_manual]{subfiles} 1 \documentclass[../main/NEMO_manual]{subfiles} 2 2 3 \begin{document} 3 4 % ================================================================ … … 6 7 \chapter{Lateral Boundary Condition (LBC)} 7 8 \label{chap:LBC} 9 8 10 \minitoc 9 11 10 12 \newpage 11 $\ $\newline % force a new ligne12 13 13 14 14 %gm% add here introduction to this chapter … … 44 44 Evaluating this quantity as, 45 45 46 \begin{equation} \label{eq:lbc_aaaa} 47 \frac{A^{lT} }{e_1 }\frac{\partial T}{\partial i}\equiv \frac{A_u^{lT} 48 }{e_{1u} } \; \delta_{i+1 / 2} \left[ T \right]\;\;mask_u 49 \end{equation} 46 \[ 47 % \label{eq:lbc_aaaa} 48 \frac{A^{lT} }{e_1 }\frac{\partial T}{\partial i}\equiv \frac{A_u^{lT} 49 }{e_{1u} } \; \delta_{i+1 / 2} \left[ T \right]\;\;mask_u 50 \] 50 51 (where mask$_{u}$ is the mask array at a $u$-point) ensures that the heat flux is zero inside land and 51 52 at the boundaries, since mask$_{u}$ is zero at solid boundaries which in this case are defined at $u$-points … … 53 54 54 55 %>>>>>>>>>>>>>>>>>>>>>>>>>>>> 55 \begin{figure}[!t] \begin{center} 56 \includegraphics[width=0.90\textwidth]{Fig_LBC_uv} 57 \caption{ \protect\label{fig:LBC_uv} 58 Lateral boundary (thick line) at T-level. 59 The velocity normal to the boundary is set to zero.} 60 \end{center} \end{figure} 56 \begin{figure}[!t] 57 \begin{center} 58 \includegraphics[width=0.90\textwidth]{Fig_LBC_uv} 59 \caption{ 60 \protect\label{fig:LBC_uv} 61 Lateral boundary (thick line) at T-level. 62 The velocity normal to the boundary is set to zero. 63 } 64 \end{center} 65 \end{figure} 61 66 %>>>>>>>>>>>>>>>>>>>>>>>>>>>> 62 67 … … 78 83 79 84 %>>>>>>>>>>>>>>>>>>>>>>>>>>>> 80 \begin{figure}[!p] \begin{center} 81 \includegraphics[width=0.90\textwidth]{Fig_LBC_shlat} 82 \caption{ \protect\label{fig:LBC_shlat} 83 lateral boundary condition 84 (a) free-slip ($rn\_shlat=0$); 85 (b) no-slip ($rn\_shlat=2$); 86 (c) "partial" free-slip ($0<rn\_shlat<2$) and 87 (d) "strong" no-slip ($2<rn\_shlat$). 88 Implied "ghost" velocity inside land area is display in grey. } 89 \end{center} \end{figure} 85 \begin{figure}[!p] 86 \begin{center} 87 \includegraphics[width=0.90\textwidth]{Fig_LBC_shlat} 88 \caption{ 89 \protect\label{fig:LBC_shlat} 90 lateral boundary condition 91 (a) free-slip ($rn\_shlat=0$); 92 (b) no-slip ($rn\_shlat=2$); 93 (c) "partial" free-slip ($0<rn\_shlat<2$) and 94 (d) "strong" no-slip ($2<rn\_shlat$). 95 Implied "ghost" velocity inside land area is display in grey. 96 } 97 \end{center} 98 \end{figure} 90 99 %>>>>>>>>>>>>>>>>>>>>>>>>>>>> 91 100 … … 106 115 Therefore, the vorticity along the coastlines is given by: 107 116 108 \[ 109 \zeta \equiv 2 \left(\delta_{i+1/2} \left[e_{2v} v \right] - \delta_{j+1/2} \left[e_{1u} u \right] \right) / \left(e_{1f} e_{2f} \right) \ , 110 \] 111 where $u$ and $v$ are masked fields. 112 Setting the mask$_{f}$ array to $2$ along the coastline provides a vorticity field computed with 113 the no-slip boundary condition, simply by multiplying it by the mask$_{f}$ : 114 \begin{equation} \label{eq:lbc_bbbb} 115 \zeta \equiv \frac{1}{e_{1f} {\kern 1pt}e_{2f} }\left( {\delta_{i+1/2} 116 \left[ {e_{2v} \,v} \right]-\delta_{j+1/2} \left[ {e_{1u} \,u} \right]} 117 \right)\;\mbox{mask}_f 118 \end{equation} 117 \[ 118 \zeta \equiv 2 \left(\delta_{i+1/2} \left[e_{2v} v \right] - \delta_{j+1/2} \left[e_{1u} u \right] \right) / \left(e_{1f} e_{2f} \right) \ , 119 \] 120 where $u$ and $v$ are masked fields. 121 Setting the mask$_{f}$ array to $2$ along the coastline provides a vorticity field computed with 122 the no-slip boundary condition, simply by multiplying it by the mask$_{f}$ : 123 \[ 124 % \label{eq:lbc_bbbb} 125 \zeta \equiv \frac{1}{e_{1f} {\kern 1pt}e_{2f} }\left( {\delta_{i+1/2} 126 \left[ {e_{2v} \,v} \right]-\delta_{j+1/2} \left[ {e_{1u} \,u} \right]} 127 \right)\;\mbox{mask}_f 128 \] 119 129 120 130 \item["partial" free-slip boundary condition (0$<$\np{rn\_shlat}$<$2):] the tangential velocity at … … 182 192 183 193 %>>>>>>>>>>>>>>>>>>>>>>>>>>>> 184 \begin{figure}[!t] \begin{center} 185 \includegraphics[width=1.0\textwidth]{Fig_LBC_jperio} 186 \caption{ \protect\label{fig:LBC_jperio} 187 setting of (a) east-west cyclic (b) symmetric across the equator boundary conditions.} 188 \end{center} \end{figure} 194 \begin{figure}[!t] 195 \begin{center} 196 \includegraphics[width=1.0\textwidth]{Fig_LBC_jperio} 197 \caption{ 198 \protect\label{fig:LBC_jperio} 199 setting of (a) east-west cyclic (b) symmetric across the equator boundary conditions. 200 } 201 \end{center} 202 \end{figure} 189 203 %>>>>>>>>>>>>>>>>>>>>>>>>>>>> 190 204 … … 202 216 203 217 %>>>>>>>>>>>>>>>>>>>>>>>>>>>> 204 \begin{figure}[!t] \begin{center} 205 \includegraphics[width=0.90\textwidth]{Fig_North_Fold_T} 206 \caption{ \protect\label{fig:North_Fold_T} 207 North fold boundary with a $T$-point pivot and cyclic east-west boundary condition ($jperio=4$), 208 as used in ORCA 2, 1/4, and 1/12. 209 Pink shaded area corresponds to the inner domain mask (see text). } 210 \end{center} \end{figure} 218 \begin{figure}[!t] 219 \begin{center} 220 \includegraphics[width=0.90\textwidth]{Fig_North_Fold_T} 221 \caption{ 222 \protect\label{fig:North_Fold_T} 223 North fold boundary with a $T$-point pivot and cyclic east-west boundary condition ($jperio=4$), 224 as used in ORCA 2, 1/4, and 1/12. 225 Pink shaded area corresponds to the inner domain mask (see text). 226 } 227 \end{center} 228 \end{figure} 211 229 %>>>>>>>>>>>>>>>>>>>>>>>>>>>> 212 230 … … 260 278 261 279 %>>>>>>>>>>>>>>>>>>>>>>>>>>>> 262 \begin{figure}[!t] \begin{center} 263 \includegraphics[width=0.90\textwidth]{Fig_mpp} 264 \caption{ \protect\label{fig:mpp} 265 Positioning of a sub-domain when massively parallel processing is used. } 266 \end{center} \end{figure} 280 \begin{figure}[!t] 281 \begin{center} 282 \includegraphics[width=0.90\textwidth]{Fig_mpp} 283 \caption{ 284 \protect\label{fig:mpp} 285 Positioning of a sub-domain when massively parallel processing is used. 286 } 287 \end{center} 288 \end{figure} 267 289 %>>>>>>>>>>>>>>>>>>>>>>>>>>>> 268 290 … … 279 301 The whole domain dimensions are named \np{jpiglo}, \np{jpjglo} and \jp{jpk}. 280 302 The relationship between the whole domain and a sub-domain is: 281 \ begin{align}282 jpi & = & ( jpiglo-2*jpreci + (jpni-1) ) / jpni + 2*jpreci \nonumber \\283 jpj & = & ( jpjglo-2*jprecj + (jpnj-1) ) / jpnj + 2*jprecj \label{eq:lbc_jpi}284 \ end{align}303 \[ 304 jpi = ( jpiglo-2*jpreci + (jpni-1) ) / jpni + 2*jpreci 305 jpj = ( jpjglo-2*jprecj + (jpnj-1) ) / jpnj + 2*jprecj 306 \] 285 307 where \jp{jpni}, \jp{jpnj} are the number of processors following the i- and j-axis. 286 308 … … 289 311 An element of $T_{l}$, a local array (subdomain) corresponds to an element of $T_{g}$, 290 312 a global array (whole domain) by the relationship: 291 \begin{equation} \label{eq:lbc_nimpp} 292 T_{g} (i+nimpp-1,j+njmpp-1,k) = T_{l} (i,j,k), 293 \end{equation} 313 \[ 314 % \label{eq:lbc_nimpp} 315 T_{g} (i+nimpp-1,j+njmpp-1,k) = T_{l} (i,j,k), 316 \] 294 317 with $1 \leq i \leq jpi$, $1 \leq j \leq jpj $ , and $1 \leq k \leq jpk$. 295 318 … … 335 358 336 359 %>>>>>>>>>>>>>>>>>>>>>>>>>>>> 337 \begin{figure}[!ht] \begin{center} 338 \includegraphics[width=0.90\textwidth]{Fig_mppini2} 339 \caption { \protect\label{fig:mppini2} 340 Example of Atlantic domain defined for the CLIPPER projet. 341 Initial grid is composed of 773 x 1236 horizontal points. 342 (a) the domain is split onto 9 \time 20 subdomains (jpni=9, jpnj=20). 343 52 subdomains are land areas. 344 (b) 52 subdomains are eliminated (white rectangles) and 345 the resulting number of processors really used during the computation is jpnij=128.} 346 \end{center} \end{figure} 360 \begin{figure}[!ht] 361 \begin{center} 362 \includegraphics[width=0.90\textwidth]{Fig_mppini2} 363 \caption { 364 \protect\label{fig:mppini2} 365 Example of Atlantic domain defined for the CLIPPER projet. 366 Initial grid is composed of 773 x 1236 horizontal points. 367 (a) the domain is split onto 9 \time 20 subdomains (jpni=9, jpnj=20). 368 52 subdomains are land areas. 369 (b) 52 subdomains are eliminated (white rectangles) and 370 the resulting number of processors really used during the computation is jpnij=128. 371 } 372 \end{center} 373 \end{figure} 347 374 %>>>>>>>>>>>>>>>>>>>>>>>>>>>> 348 375 … … 400 427 The choice of algorithm is currently as follows: 401 428 402 \mbox{}403 404 429 \begin{itemize} 405 430 \item[0.] No boundary condition applied. … … 410 435 ({\it dynspg\_ts}). 411 436 \end{itemize} 412 413 \mbox{}414 437 415 438 The main choice for the boundary data is to use initial conditions as boundary data … … 445 468 a zone next to the edge of the model domain. 446 469 Given a model prognostic variable $\Phi$ 447 \begin{equation} \label{eq:bdy_frs1} 448 \Phi(d) = \alpha(d)\Phi_{e}(d) + (1-\alpha(d))\Phi_{m}(d)\;\;\;\;\; d=1,N 449 \end{equation} 470 \[ 471 % \label{eq:bdy_frs1} 472 \Phi(d) = \alpha(d)\Phi_{e}(d) + (1-\alpha(d))\Phi_{m}(d)\;\;\;\;\; d=1,N 473 \] 450 474 where $\Phi_{m}$ is the model solution and $\Phi_{e}$ is the specified external field, 451 475 $d$ gives the discrete distance from the model boundary and … … 453 477 It can be shown that this scheme is equivalent to adding a relaxation term to 454 478 the prognostic equation for $\Phi$ of the form: 455 \begin{equation} \label{eq:bdy_frs2} 456 -\frac{1}{\tau}\left(\Phi - \Phi_{e}\right) 457 \end{equation} 479 \[ 480 % \label{eq:bdy_frs2} 481 -\frac{1}{\tau}\left(\Phi - \Phi_{e}\right) 482 \] 458 483 where the relaxation time scale $\tau$ is given by a function of $\alpha$ and the model time step $\Delta t$: 459 \begin{equation} \label{eq:bdy_frs3} 460 \tau = \frac{1-\alpha}{\alpha} \,\rdt 461 \end{equation} 484 \[ 485 % \label{eq:bdy_frs3} 486 \tau = \frac{1-\alpha}{\alpha} \,\rdt 487 \] 462 488 Thus the model solution is completely prescribed by the external conditions at the edge of the model domain and 463 489 is relaxed towards the external conditions over the rest of the FRS zone. … … 466 492 467 493 The function $\alpha$ is specified as a $tanh$ function: 468 \begin{equation} \label{eq:bdy_frs4} 469 \alpha(d) = 1 - \tanh\left(\frac{d-1}{2}\right), \quad d=1,N 470 \end{equation} 494 \[ 495 % \label{eq:bdy_frs4} 496 \alpha(d) = 1 - \tanh\left(\frac{d-1}{2}\right), \quad d=1,N 497 \] 471 498 The width of the FRS zone is specified in the namelist as \np{nn\_rimwidth}. 472 499 This is typically set to a value between 8 and 10. … … 532 559 533 560 %>>>>>>>>>>>>>>>>>>>>>>>>>>>> 534 \begin{figure}[!t] \begin{center} 535 \includegraphics[width=1.0\textwidth]{Fig_LBC_bdy_geom} 536 \caption { \protect\label{fig:LBC_bdy_geom} 537 Example of geometry of unstructured open boundary} 538 \end{center} \end{figure} 561 \begin{figure}[!t] 562 \begin{center} 563 \includegraphics[width=1.0\textwidth]{Fig_LBC_bdy_geom} 564 \caption { 565 \protect\label{fig:LBC_bdy_geom} 566 Example of geometry of unstructured open boundary 567 } 568 \end{center} 569 \end{figure} 539 570 %>>>>>>>>>>>>>>>>>>>>>>>>>>>> 540 571 … … 553 584 (and therefore restrictions on the order of the data in the file). 554 585 In particular: 555 556 \mbox{}557 586 558 587 \begin{enumerate} … … 564 593 \end{enumerate} 565 594 566 \mbox{}567 568 595 These restrictions mean that data files used with previous versions of the model may not work with version 3.4. 569 596 A fortran utility {\it bdy\_reorder} exists in the TOOLS directory which … … 571 598 572 599 %>>>>>>>>>>>>>>>>>>>>>>>>>>>> 573 \begin{figure}[!t] \begin{center} 574 \includegraphics[width=1.0\textwidth]{Fig_LBC_nc_header} 575 \caption { \protect\label{fig:LBC_nc_header} 576 Example of the header for a \protect\ifile{coordinates.bdy} file} 577 \end{center} \end{figure} 600 \begin{figure}[!t] 601 \begin{center} 602 \includegraphics[width=1.0\textwidth]{Fig_LBC_nc_header} 603 \caption { 604 \protect\label{fig:LBC_nc_header} 605 Example of the header for a \protect\ifile{coordinates.bdy} file 606 } 607 \end{center} 608 \end{figure} 578 609 %>>>>>>>>>>>>>>>>>>>>>>>>>>>> 579 610 … … 608 639 To be written.... 609 640 610 611 641 \biblio 612 642 613 643 \end{document}
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