Laserfiche WebLink
<br />44 <br /> <br />e <br /> <br />Recommendations for Vurther Study <br />There are two areas where accuracy of solution could be improved; <br /> <br />these relate to constants used in the weir equation and comparison to <br /> <br />e <br /> <br />observed flows. It seems that this approach could be greatly improved <br /> <br />upon by a study of the full spectrum of stream types which could flow <br />near critical. The objective of the study should be to define a re- <br /> <br />lation between descriptors of cross-sectional geometry in control <br /> <br />sections and values of the constants C and m. Parameters used <br />s <br />to describe cross-sections could include wetted perimeter, area, top <br /> <br />width, side slopes and possibly a term for sizes of bed material, if <br />such sizes exerted a significant effect on hydraulics of the section. <br />Ideally, if a mathematical expression could be obtained for the values <br /> <br />of C and m in terms of quantifiable section properties, such an <br />s <br />expression could be incorporated into the subroutine for computation <br /> <br />. <br /> <br />of flow at a control section. In any case, the definition of values <br /> <br />of the coefficients for various types of cross sections would greatly <br /> <br />extend applicability of the program. <br /> <br />Accuracy of all available water surface profile programs could <br /> <br />be improved upon by a refinement in the method of determining eddy <br /> <br />losses that result from expanding and contracting sections. All <br />existing programs estimate eddy losses as a percentage of velocity <br /> <br />head differential between two sections. Thus the basis for computation <br /> <br />of eddy losses is a quantity only indirectly related to such losses; <br /> <br />there is no current method used in water surface profile programs which <br /> <br />. <br /> <br />relates eddy losses to channel geometry. Development of such a <br /> <br />relation would increase accuracy of all programs currently in use and <br /> <br />would be of particular benefit in reduction. of the need for estimation <br />