Sand transport and deposition within arrays of non-erodible cylindrical elements
✍ Scribed by Al-Awadhi, Jasem M.; Willetts, Brian B.
- Book ID
- 102645951
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 549 KB
- Volume
- 24
- Category
- Article
- ISSN
- 0360-1269
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✦ Synopsis
The study concerns sand deposition within a regular array of vertical cylinders placed in the path of a sand-laden wind. Twelve wind tunnel experiments using three preselected shear velocities (28Á78, 32Á86 and 45Á1 cm s À1 ), with associated rates of sand feed (0Á3, 2Á0 and 3Á8 g cm À1 s À1 ), and four roughness element concentrations (! = 0Á046, 0Á092, 0Á184 and 0Á369) were carried out to evaluate the factors that affect sand deposition and sand flux in the presence of immobile rough elements. The measurements showed that as the concentration of non-erodible elements increased, the percentage reduction in the initial sand flux increased and a particularly sharp reduction occurred when ! ! 0Á18. The pattern of reduction was found to be q red = q eq (d/H) [Áy/(ÁyÀd)](0Á68 À3Á5!) when ! 0Á18, and q red = q eq (d/H)Áy/(ÁyÀd) when ! b 0Á18, where q eq is the equilibrium rate of sand transport arriving at the best bed, d is the diameter of the cylinder, H is the height of the cylinder, and Áy is the width of unit area associated with a cylinder.
The experimenal results also showed that the sand flux downstream of the array started to increase immediately upon the commencement of burial of the array's cylinders. Thus the sand deposition and sand flux along an array consisting of regularly distributed, non-erodible elements were shown to be neither uniform nor steady.