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<br />I ", > <br />, >~~- <br />- . ~ ~~. <br /> <br />" '<. <br />"" _\: <br />-,' <br />F -, <br /> <br />, <br />, . <br />h~ 1110-2-1601 <br />Appendix IV <br />1 July 70 <br /> <br />I,' <br /> <br />should be evaluated separately. Computations are presented in plate IV-4 <br /> <br />showing the use of the Alpha computation results for determining an effective <br />. <br /> <br />channel k value and the relation between k and n. <br /> <br />5. Energy Correction Factor. The velocity head correction factor (ref -10, <br /> <br /> <br />pp 7-10 in 4th ed.) is expressed as <br /> <br />or <br /> <br />A <br /> <br />a = A~3 J <br />o <br />where a is the veloCity head correction factor, V is the'mean velocity of <br />the section, and V is the mean velocity in the vertical at horizontalloca- <br />x <br />tion x throughout the cross section. The mean velocity may be expressed <br /> <br />V3 ciA <br />x <br /> <br />(IV-7) <br /> <br />Computat <br />the energ <br />feet of th, <br /> <br />ness valu <br /> <br /> A <br /> J V xclA. <br />;' <br />\ <br />V= 0 (IV -8) <br /> A <br /> <br />Substituting equation IV -8 in IV -7 yields <br /> <br />A <br /> <br />A2 J <br /> <br />o <br /> <br /> <br />· . ({ V x dA )' <br /> <br />V3 dA <br />x <br /> <br />(IV -9) <br /> <br />Substituting the relation given by equation IV -1 into equation IV -9 yields <br /> <br />a= <br /> <br />A <br />A2 f (CR1/2): ciA <br /> <br />o <br /> <br /> <br />[{ (cR'/Z). dA r <br /> <br />(IV -10) <br /> <br />\" <br /> <br />IV-4 <br /> <br />I <br />I <br /> <br />1 <br />