Changeset 40 for palm/trunk/DOC/app/chapter_4.1.html
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- Mar 2, 2007 6:32:25 AM (18 years ago)
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palm/trunk/DOC/app/chapter_4.1.html
r5 r40 1786 1786 1787 1787 1788 <td style="vertical-align: top;"><span style="font-style: italic;">' neumann'</span></td>1788 <td style="vertical-align: top;"><span style="font-style: italic;">'initial gradient'</span></td> 1789 1789 1790 1790 … … 1831 1831 1832 1832 <p>Allowed are the values <span style="font-style: italic;">'dirichlet' 1833 </span>(pt(k=nz) and pt(k=nz+1) 1834 do not change during the run) and <span style="font-style: italic;">'neumann'</span>. 1835 With the Neumann boundary 1836 condition the value of the temperature gradient at the top is 1833 </span>(pt(k=nz+1) 1834 does not change during the run), <span style="font-style: italic;">'neumann'</span> (pt(k=nz+1)=pt(k=nz)), and <span style="font-style: italic;">'initial_gradient'</span>. 1835 With the 'initial_gradient'-condition the value of the temperature gradient at the top is 1837 1836 calculated from the initial 1838 1837 temperature profile (see <a href="#pt_surface">pt_surface</a>, <a href="#pt_vertical_gradient">pt_vertical_gradient</a>) 1839 by bc_pt_t_val = (pt_init(k=nz ) -1840 pt_init(k=nz -1)) / dzu(nz).<br>1838 by bc_pt_t_val = (pt_init(k=nz+1) - 1839 pt_init(k=nz)) / dzu(nz+1).<br> 1841 1840 1842 1841 … … 1871 1870 1872 1871 1873 <ul> 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 <p style="font-style: normal;">pt(k=nz) = pt(k=nz-1) + 1895 bc_pt_t_val * dzu(nz)</p> 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 </ul> 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 <p style="font-style: normal;">and </p> 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1938 1894 1939 1895 … … 2020 1976 2021 1977 2022 <p style="font-style: normal;">(up to k=nz-1 the prognostic 2023 equation for the temperature is solved).</p> 1978 <p style="font-style: normal;">(up to k=nz the prognostic 1979 equation for the temperature is solved).<br> 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 When a constant sensible heat flux is used at the top boundary (<a href="chapter_4.1.html#top_heatflux">top_heatflux</a>), <b>bc_pt_t</b> = <span style="font-style: italic;">'neumann'</span> 1991 must be used, because otherwise the resolved scale may contribute to 1992 the top flux so that a constant value cannot be guaranteed.</p> 2024 1993 2025 1994 … … 2345 2314 2346 2315 2347 <ul> 2348 2349 2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 <p style="font-style: normal;">q(k=nz) = q(k=nz-1) + 2369 bc_q_t_val * dzu(nz)</p> 2370 2371 2372 2373 2374 2375 2376 2377 2378 2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 </ul> 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 <p style="font-style: normal;">and </p> 2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337 2412 2338 2413 2339 … … 2494 2420 2495 2421 2496 <p style="font-style: normal;">(up tp k=nz -1the prognostic2422 <p style="font-style: normal;">(up tp k=nz the prognostic 2497 2423 equation for q is solved). </p> 2498 2424 … … 2819 2745 2820 2746 2821 <ul> 2822 2823 2824 2825 2826 2827 2828 2829 2830 2831 2832 2833 2834 2835 2836 2837 2838 2839 2840 2841 2842 <p style="font-style: normal;">s(k=nz) = s(k=nz-1) + 2843 bc_s_t_val * dzu(nz)</p> 2844 2845 2846 2847 2848 2849 2850 2851 2852 2853 2854 2855 2856 2857 2858 2859 2860 2861 2862 2863 2864 </ul> 2865 2866 2867 2868 2869 2870 2871 2872 2873 2874 2875 2876 2877 2878 2879 2880 2881 2882 2883 2884 2885 <p style="font-style: normal;">and </p> 2747 2748 2749 2750 2751 2752 2753 2754 2755 2756 2757 2758 2759 2760 2761 2762 2763 2764 2765 2766 2767 2768 2886 2769 2887 2770 … … 2968 2851 2969 2852 2970 <p style="font-style: normal;">(up to k=nz -1the prognostic2853 <p style="font-style: normal;">(up to k=nz the prognostic 2971 2854 equation for the scalar concentration is 2972 2855 solved).</p> … … 14687 14570 logarithmic wind and temperature 14688 14571 profiles between k=0 and k=1. In this case a Dirichlet condition (see <a href="#bc_pt_b">bc_pt_b</a>) 14689 must be used as bottom boundary condition for the potential temperature.</p> 14572 must be used as bottom boundary condition for the potential temperature.</p><p>See also <a href="#top_heatflux">top_heatflux</a>.</p> 14690 14573 14691 14574 … … 16807 16690 16808 16691 16809 <tr> 16692 <tr><td style="vertical-align: top;"><a name="top_heatflux"></a><span style="font-weight: bold;">top_heatflux</span></td><td style="vertical-align: top;">R</td><td style="vertical-align: top;"><span style="font-style: italic;">no prescribed<br> 16693 heatflux</span></td><td style="vertical-align: top;"><p>Kinematic sensible heat flux at the top boundary (in K m/s). </p> 16694 16695 16696 16697 16698 16699 16700 16701 16702 16703 16704 16705 16706 16707 16708 16709 16710 16711 16712 16713 16714 <p>If a value is assigned to this parameter, the internal two-dimensional surface heat flux field <span style="font-family: monospace;">tswst</span> is initialized with the value of <span style="font-weight: bold;">top_heatflux</span> as top (horizontally homogeneous) boundary condition for the 16715 temperature equation. This additionally requires that a Neumann 16716 condition must be used for the potential temperature (see <a href="chapter_4.1.html#bc_pt_t">bc_pt_t</a>), 16717 because otherwise the resolved scale may contribute to 16718 the top flux so that a constant value cannot be guaranteed.<span style="font-style: italic;"></span> </p> 16719 16720 16721 16722 16723 16724 16725 <p><span style="font-weight: bold;">Note:</span><br>The application of a top heat flux additionally requires the setting of initial parameter <a href="#use_top_fluxes">use_top_fluxes</a> = .T..<span style="font-style: italic;"></span><span style="font-weight: bold;"></span> </p><p>No Prandtl-layer is available at the top boundary so far.</p><p>See also <a href="#surface_heatflux">surface_heatflux</a>.</p> 16726 16727 16728 16729 16730 16731 16732 16733 16734 16735 16736 16737 16738 16739 16740 16741 16742 16743 16744 16745 16746 </td></tr><tr> 16810 16747 16811 16748 … … 18336 18273 18337 18274 18338 <tr> 18275 <tr><td style="vertical-align: top;"><a name="use_top_fluxes"></a><span style="font-weight: bold;">use_top_fluxes</span></td><td style="vertical-align: top;">L</td><td style="vertical-align: top;"><span style="font-style: italic;">.F.</span></td><td style="vertical-align: top;"> 18276 18277 18278 18279 18280 18281 18282 18283 18284 18285 18286 18287 18288 18289 18290 18291 18292 18293 18294 18295 18296 18297 18298 18299 18300 18301 18302 18303 18304 18305 18306 18307 18308 18309 18310 18311 18312 18313 18314 18315 18316 18317 18318 18319 18320 18321 18322 18323 18324 18325 18326 18327 18328 18329 18330 18331 18332 18333 18334 18335 18336 18337 18338 <p>Parameter to steer the treatment of the subgrid-scale vertical 18339 fluxes within the diffusion terms at k=nz (top boundary).</p><p>By default, the fluxes at nz are calculated using the gradient approach. If <b>use_top_fluxes</b> 18340 = <i>.TRUE.</i>, the user-assigned top fluxes are used instead 18341 (see <a href="chapter_4.1.html#top_heatflux">top_heatflux</a>).</p><p>Currently, only a value for the sensible heatflux can be assigned. In case of <span style="font-weight: bold;">use_top_fluxes</span> = <span style="font-style: italic;">.TRUE.</span>, the latent heat flux at the top will be automatically set to zero.</p></td></tr><tr> 18339 18342 18340 18343
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