Numerical flow model stepped spillways in order to maximize energy dissipation using FLUENT software

Moussa Rassaei
2014 IOSR Journal of Engineering  
Stepped spillway energy dissipation has a synergistic effect. In the present study, to identify, the effect of various parameters such as the number of steps (N), the step height (h), the length step (L) and the discharge per unit width (q) on energy dissipation in stepped spillways simple numerical is used numerical method. Relationshipships between the critical depth flow and energy dissipation are presented and discussed in stepped spillways. In this study for solving the governing equations
more » ... governing equations detachable, the finite volume method (Fluent Software) and to assess turbulence flow, is used the standard k-ε models. The regular mesh, is used in a Specified boundary condition and the volume of fluid method (VOF) is used to solve the free-surface flow. Free surface flow,Velocities and pressures in stepped spillway, is modeling by Confused numerical method. The numerical results were compared with Experimental results of other researchers, and the results are a good agreement and the errors Variations is one of the 2%. The results of this study show that with increasingthe flow rate and also by fixed dam height and with increasing the number of steps, is reduced energy dissipation. Keywords: -stepped spillway, FLUENT numerical model, turbulence model − , volume of fluid (VOF ) model I. INTRODUCTION The Stepped spillway consists of steps that starts of near spillway crest and continues downstream heels. The use of a stepped spillway, has been common since ancient times. But, because of the significant impact of steps, on the energy dissipation flow, in recent years, due to this type of Spillways has been greater. Also, understanding new technologies, the use of Materials, Roller compact Concrete and consistent the manufacturing method with spillway mentioned, make use of stepped Spillways has a large number of projects. Stepped spillway, is a hydraulic structures, very powerful of Climactic spillway in Amortize the flow energy and reduce erosion downstream of the dams. When the water flow by spillway from the reservoir to water surface in downstream, to falls, the potential energy is converted to kinetic energy. This energy, in the form high-speed in downstream is appears, that, for the prevention of river erosion in downstream, is necessary to install facilities such as Stepped spillways, is amortized. The rate of High energy dissipation, established by the Steps, the caused Drilling deep stilling basin downstream, length of stilling basin and height of the side walls, dropped and this point of view, great savings comes into operation. Salmasi In 1382, calculated and evaluated the reat of energy dissipation in stepped spillways for every steps different by using of experimental work, and showed that, Calculating the energy dissipation in downstream, by using of water depth After the hydraulic jump, to reality is nearer and more accurate [1]. Naderi Rad in 1386 by using of FLUENT numerical model, calculated the energy dissipation in types of simple stepped spillways, edges and Slopes [2]. Spalding and laundr in (1972) the first people who offered the k-ε model [3]. Christodoulou in 1993, offered method for calculated energy dissipation in stepped spillway by continuous flow [4]. Chamani & Rajatnam in 1994, offered method, for investigate the rate of energy dissipation in nappe flow regime [5]. James and Partners in 2001, offered a new model for Steps of stepped spillway. in this new model, has been made the edge of steps in the form (V) [6]. Chen and Partners in 2002, analyzed flow over the stepped spillway, by using of the finite-volume method , and the k-ε model, used to determine turbulence flow [7]. Boes and Hager in 2003, offered an algorithm to calculate the residual energy and not depreciated in stepped spillway. All of these relationshipships are based on experimental works [8]. Chatila and Tabbara in 2004, analyzed Climactic spillway by using the finite element method and the k-ε model used to determine turbulence flow in the Climactic spillway [9] . Tabbara and Partners in 2005, were analyzed the stepped spillway by using the finite element method and the Kε model have benefited to determine turbulence flow in the stepped spillway [10] . In this research, is used of the Fluent numerical model , which it works based on the finite volume method and for determination the free surface flow has been used the volume of fluid method (VOF) and for the turbulence flow has been used of the standard K-ε model. And the continue energy dissipation were calculated on per number of steps 5th and 10th and compared with experimental results of other researchers, and calculated the error rate and will be discussed performance of the FLUENT model.
doi:10.9790/3021-04651725 fatcat:djzlbqijgrcalcsnqmycjwkcq4