BROAD-CKESTED WEIRS 



168 



Survey and for the United States Board of Engineers on Deep Waterways 

 the weirs were 16 feet in length and heads up to 4 feet were used. The 

 Cornell experiments were by far the more extensive, and the chief results 

 of these are shown by the following tables and the diagrams of Fig. 89 A, B, 

 and c. On all weirs having vertical down-stream faces the nappe was fully 

 aerated. In the weirs with inclined down-stream faces no air was admitted 

 under the nappe. 



RECTANGULAR FLAT-CRESTED WEIRS. 

 Values of K' in formula, Q = A" b H%. 



COMPOUND WEIRS (A TO F). FIG. 89A. 



From experiments on weirs of ogee cross section (A to F), the 

 formula 



K' = | 3-62 - -16 - 1) j H^ 



was found to give the coefficient with reasonable accuracy. Here s is the 

 slope of the up-stream face. 



M 2 



