REGIMES OF FLOW AND RESISTANCE TO FLOW IN ALLUVIAL RIVERS

Abstract

The various bed forms obtained in alluvial streams are ripples, dunes, transition and antidunes. Knowledge of the bed form occurring in a stream at given flow conditions is important in several problems connected with the resistance to flow and sediment transport in alluvial channel. This thesis presents the results of the analysis carried out to verify different criteria for prediction of regime of flow and resistance equations. The vast amount of natural river data covering wide range collected from different sources are used for this verification, The analysis is carried out to cover the following aspects: 1. Verification of existing methods to predict regimes of flow, 2. Verification of existing method to predict resistance to flow, To explore the possibility of determining the new power relationship for alluvial channel resistance. pY 2. The relation betweenAYs and )P s/( Y1 R . if is slightly better if p = T than p = 3as proposed by Garde — Ranga Raju. 3. Values of Ki and K2 in the relation K1 / p s R R 1/3 = f (K2 ( a ) as ) for coarse material need some modification. 0.8 = f(R/d\ 4. The resistance'irelationship f(U_/050 ) / is doing work well for Japanese rivers.ItA.s required further verification with additional natural data covering wide range to improve its accuracy for prediCtion of mean velocity