مشخصات پژوهش

عنوان	Form friction factor of armored river beds
نوع پژوهش	مقاله چاپ‌شده در مجلات علمی
کلیدواژه‌ها	Armor layer, Bed form, Gravel-bed river, Friction factor, Shields parameter
چکیده	Resistance to flow because of the presence of bed forms over armored river beds is of paramount importance, leading to the effective design of water-resources-related projects. Based on the findings over bed armored surfaces, it is shown that the controlling roughness ( ) can be taken as ks equal to the median diameter of the armor layer. Analytical methodologies for total and grain friction factors have been proposed here which take flow non-uniformity into account using the velocity distribution and friction slope. The percentage composition of form friction factor in the total friction factor was estimated to be 40%. The results were explained in light of the coupling of the sediment threshold problem with the friction factor and coarse-grain rearrangement in armor layer. The computed form friction factor by proposed method was compared with Keulegan’s method and is found to give satisfactory results, showing 80% agreement of all field data sets.
پژوهشگران	سیدسعید اخروی (نفر اول)، سعید گوهری (نفر دوم)