Develop of Flow Resistance Equations in Mountain Rivers Based On Experimental Study

Document Type : Research Paper



     The aim of this research is to develop relations to estimate the flow resistance coefficients in gravel-bed channels. In this regards, the experiments were carried out in a tilting flume with length of 8m and width of 0.25m. In this research, four different bed slopes (0.004, 0.006, 0.008 and 0.01), two gravel types (natural and crushed shapes), three mean diameter (d50) of gravels (65.3, 46.6 and 38 mm) and four discharges (0.01, 0.017, 0.024 and .031 m3/s) were used as a variables. New flow resistance equations were developed for natural and crushed gravels by using the new definitions for dimensionless variables in terms of non-dimensional hydraulic geometry equations. Also, new equations were presented to estimate Manning’s roughness coefficient for both shapes.  In addition, the results showed that the developed equations based on non-dimensional hydraulic geometry relations are the best way to link the mean flow velocity to the flow discharge in mountain rivers.


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Volume 40, 1-1
Special Issue
June 2017
Pages 13-25
  • Receive Date: 01 November 2015
  • Revise Date: 07 June 2017
  • Accept Date: 19 December 2015
  • Publish Date: 01 January 1970