Experimental study of suspended load effect on flow friction factor on rigid and smooth beds

The effect of suspended load on friction coefficient has been studied widely by different researchers، yet vast disagreement exists among them which call for further studies in this area. In this study، the effect of suspended load on flow friction coefficient on smooth and rigid beds was experimentally studied. The experimental setup that was used for this study، consists of a 0. 2m wide، 20. 4m long and 0. 3m deep flume، a water reservation tank and sediment mixture tank. A special sediment sampler has been developed for this study and the discharge was measured by using an orifice that was previously calibrated. The compiled data of this study indicated no impact to decrease friction coefficient. Also it is shown that the variation of the friction coefficient depends on particle Reynolds number. The obtained results was compared with that of other researchers results and which revealed that Parker-Coleman''s relationship could be considered as the most appropriate one for determining the effect of suspended load on flow friction coefficient.