Author(s): Masoud Arami Fadafan; Masoud-Reza Hessami Kermani
Linked Author(s):
Keywords: Mesh free particle methods; Moving Particle Semi-implicit; Ogee spillway; Flow-3D
Abstract: Mesh free methods are used in wide range of engineering problems such as astrophysics, continuum solid, fluid mechanics and heat transfer. Mesh free particles based methods are suitable to simulate flows with large deformations and fragmentations due to using discrete particles. Despite of capabilities of these methods, they are rarely used for modeling of open channel flows, specially in the case of ogee spillways. Usually based mesh methods such as finite volume, finite element or finite difference are used to simulate open channel problems which have provided sat isfactory results, however their success rely on good meshes. In the Eulerian methods, numerical diffusion due to advection terms may be severe which is eliminated in Lagarangian methods due to the existence of advection terms in the Navier-stokes equations. Furthermore, detecting of the free surface is a complicated procedure in the Eulerian methods which is simply identified in Lagrangian methods using a simple criterion. In this paper, flow over an ogee spillway is modeled using an incompressible Moving Particle Semi-implicit (MPS) method which is a fully Lagrangain meshless method. The governing equations are mass and momentum conservation that are solved in Lagrangian form using a two-step fractional method. In the first step momentum equation is solved without considering the pressure term. In this step velocity field and the position of particles are computed but incompressibility is neglected. In the second step, to satisfy the incompressibility condition, the continuity constraint is considered and the Poisson equation is solved to compute the pressure values of fluid and wall particles. Then the velocity field and positions of particles are corrected. The MPS results are compared with those of experimental ones in free surface comparison. Moreover, velocity and pressure fields are depicted in different times and compared with those of obtained using Flow-3D simulation. The results show the capabilities of used method in open channel flow simulations.
Year: 2015