Resistance to Flow in Sand-Bed Channels

The resistance theory is applicable to sand-bed channels, but the necessary changes are made to take care of material with higher or lower specific weights than sand. The major difference of the new approach from the ones in use is that it considers the transition regions between the major bed form categories like ripples and dunes. The bed form prediction is given in plot form and the relations defining the roughness are semilogarithmic in form, similar to Prandtl-von Karman velocity distribution law. Five sets of data are used to develop the approach. The data used cover flume, canal, and river studies. Thus the study includes a wide variety of flow conditions. The approach presented is compared with other semilogarithmic approaches. It can be used in the lower flow regime to predict resistance to flow with reasonable accuracy.