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<br />: <br /> <br />For most of the check lines, the improvement in con- <br />tinuity obtained with increasing network detail was associated <br />with changes in both velocity and depth. In two cases, lines <br />6 & 8, the velocity changes were substantial. This region of <br />the flow field is characterized by a rapid change of direction. <br />The results reinforce the caveat that increased network detail <br />is important in such regions. Furthermore, it appears that <br />depth is somewhat less sensitive to errors in continuity than <br />is velocity. Therefore, if one is interested in water surface <br />elevations only, a less stringent continuity perfonr,ance <br />criterion could be accepted than if velocities are of interest. <br /> <br />&PILcat i o~J:~~cN a ry_pam SecondJ'-9\1_eFl1ouse_5_tudy <br />An example of a "production" type application of the horizontal <br />flow model is the second powel'house site selection study for <br />McNary lock and dam on the Columbia River. Flow fields down- <br />stream of the dam were simulated for several possible locations <br />of the second powerhouse. Of interest were velocities, both <br />magnitudes and directions, in the vicinity of the approach <br />channel to the navigation lock. The study area and several of <br />the possible second powerhouse locations are shown on Fig. 4. <br />Finite element networks for the existing condition and for the <br />south shore powerhouse with excavated discharge channel are <br />shown in Figs. 5 and 6. Data are summarized in Table 4. The <br />roughness coefficient was calibrated to reproduce an observed <br />conditi on. <br />This study was greatly facilitated by an autolcatic re- <br />ordering algorithm (Collins (1973)) which has been incorporated <br />into the model. This algorithm makes modification of a network <br />(compare Figs. 5 and 6) straightforward in that the entire <br />network need not be re-nurT,Jered. The existing numbering scheme <br />is utilized for input/output end the system of equations <br />internally re-ordered to reduce storage. <br /> <br />----- r- <br /> <br />, <br /> <br />//1' ,,'''F''-0'~$::::y _.... <br />n'''.. I .____ - . - - ~ '~""""" 'D<' <br />/~_,~"~.. ;,.' _____--.--- -"-'-<-'''~~'L'~'- <br />...."..-"-.;-y.......-.~--- <br />_ 0" .'~~L. ..'~~. <br />.....;::!-- <br />~------- - <br /> <br />,- <br /> <br />""h',_ <br />._/ <br />--- ! <br />-'- I <br />_.__ i' a <br />J <br />~.~---~~ = - 'Ii ; <br />\, -'--j '\:,:-~- <br />, ' . <br />, ., <br />~ I ,tf <br />".. ':::.::' :i:i <br />~, HIl <br />....... I!: <br />......----1E.. <br /> <br />- - <br /> <br />, <br /> <br />-;11'~-':'-:'- <br /> <br />f,'.... <br />,.I' <br /> <br />7 <br /> <br />[ ,J;o~""t- -=,l. <br />~, UOy ""[. SHOw'''''' Pe~SIllil.f <br />SrCc-.lD Kl.fRHOUSt Lou.~,OO4 <br />n._ ___ __ __.,________.__ <br />