A RESEARCH ON THE RIVER BED RESISTANCE OF CHIYODA EXPERIMENTAL FLUME

Authors did a movable bed and steady flow experiment at the Chiyoda Experimental Flume, a large scale flume located in the Chiyoda New Waterway of Tokachi River, and observed bed wave figure on the local bed materials. In this study, the steepness of the sand waves observed was first estimated using the Yalin-Karahan method, and found that the observed was only slightly less than the estimated value. Next, the normalized bed shear stress and normalized grain shear stress calculated from the observed values were compared, and were found to have similar tendencies as seen in the results of Kishi and Kuroki based on the hydraulic radius separation method. The bed shear stress was also estimated by calculating grain stress and form drag directly from sand wave forms with reference to the method of Kikkawa and Ishikawa etc., and the estimated values were found to be slightly smaller than the observed values.