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FRICTION SLOPE MODELS FOR M2 PROFILES 1
Author(s) -
Chadderton Ronald A.,
Miller Arthur C.
Publication year - 1980
Publication title -
jawra journal of the american water resources association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.957
H-Index - 105
eISSN - 1752-1688
pISSN - 1093-474X
DOI - 10.1111/j.1752-1688.1980.tb02384.x
Subject(s) - environmental science , geology , hydrology (agriculture) , physics , geotechnical engineering
Results of studies which have considered the relative merit of various friction slope averaging equations previously used in water surface profile computations are described. Limitations of the most accurate equation known for the M2 profile have indicated that a new equation which gives more emphasis to the upstream energy gradient is desirable. Based upon friction slope curves developed for M2 water surface profiles two new equations, one a parabolic and the other an elliptical approximation, are presented. The behavior of the new equations and of the previously most recommended equation is described by test calculations. The elliptical equation performed more satisfactorily than the harmonic method commonly recommended for M2 profile computations. Insertion of an additional cross‐section about 50 feet upstream from a critical depth section was found to reduce computational errors for any energy gradient averaging method.