نوع مقاله : مقاله پژوهشی
نویسندگان
1 استاد گروه مهندسی آب،دانشکده کشاورزی،دانشگاه فردوسی مشهد،ایران
2 دانشجوی دکتری سازه‌های آبی، گروه مهندسی آب، دانشگاه فردوسی مشهد، مشهد، ایران
3 دانشجوی دکتری آبیاری زهکشی،گروه مهندسی آب، دانشگاه شهید چمران اهواز، اهواز، ایران
چکیده
کلیدواژه‌ها
عنوان مقاله [English]
نویسندگان [English]
Study in mixing processes for the management of water quality of rivers is important and one of the environmental concerns. The substrates, such as dunes, are effective in control of transport, production of turbulence and flow resistance in rivers, canals and wetlands It is therefore essential that study is done in this subject. The objective of this study is to investigate the transversal mixing coefficient of dunes. For this purpose, measurements carried out on the fifth to the ninth of dunes in a series of ten dune sand of the synthetic two-dimensional. The experiments carried out in a laboratory channel with dimensions of length, width and depth, 20, 0.6 and 0.6 respectively. The dunes had a wave-length of one meter, height 0.8 meters, downstream side slopes 28 degrees and width equal to the channel width. The average diameter of sand dunes used was 14 mm. To evaluate the effect of the delicately ratio on lateral mixing coefficients, two different depths were used. The results showed that dune plays an important role in increasing the lateral mixing coefficient so that in this case this rate was 2.36 times the flat bed. Complete mixing length in the channel bed dunes was 11 meters to the amount indicated on the flat bed of a third. This parameter showed a decrease with increasing depth over the dunes. The tests indicate that the self-purification power of the river on the dunes, comparing to a flat bed, with increasing water depth above of the dunes, increases
کلیدواژه‌ها [English]
)