Numerical investigation of free surface and pipe flow problems by smoothed particle hydrodynamics

2017
Dinçer, Ali Ersin
In the present study, a two-dimensional (2D) computer code for free surface and pipe flows is developed by using Smoothed Particle Hydrodynamics (SPH) approach. For free surface flow problem, idealized dam break problems are investigated numerically. The results of three recently published experimental studies are used to validate the numerical solutions. In addition to mesh-free particle method, SPH with a novel boundary treatment model proposed in the present study, mesh-based methods with turbulence and laminar modelling are used to simulate the dam break problem. It is confirmed that SPH can be used to predict the behavior of dam-break induced flows. In addition, the computational time of SPH decreases with the proposed boundary model which is seminal for fluid-structure interaction problems with SPH. Liquid slug flow driven by pressurized air in inclined and horizontal pipes with a downstream elbow is investigated numerically for the application of SPH in pipe flows. As the liquid slug hits the elbow, the impact pressure and the associated force generated at the elbow may damage pipe supports as well as the pipe itself. The slug arrival velocity and slug length (i.e. mass) at the elbow directly affect that pressure. In order to calculate these slug parameters just before the impact an improved one-dimensional (1D) model proposed in the literature is used. At the elbow, pressure variation with respect to time is calculated with SPH. The obtained numerical data are validated with previously published experimental results. For both short and long slugs, calculated peak pressures and pressure variations show great agreement with those of measured peak pressures and pressure variations.

Suggestions

Numerical Modeling of Electromagnetic Scattering from Periodic Structures by Transformation Electromagnetics
ÖZGÜN, ÖZLEM; Kuzuoğlu, Mustafa (2016-09-22)
The transformation electromagnetics is applied to the modeling of electromagnetic scattering from periodic structures in conjunction with the finite element method with periodic boundary conditions. In a unit cell of periodic structure, a uniform mesh is used over a flat surface and the arbitrary periodic surface is modeled by a coordinate transformation. The major advantage of this approach is that arbitrary geometries can be handled by using a single and simple mesh. Therefore, repeated computations (such...
Applications of a particle simulation approach
Kabakcı, İsmail; Çöker, Demirkan; Department of Aerospace Engineering (2019)
The thesis is intended to utilize a particle simulation approach, introduced for simple particles, for engineering problems in order to study and understand fluid behavior at molecular level. First, an improvement in force potential estimation is proposed for the original method, which offers notable accuracy increase in simulations in terms of determination of position and momentum trajectories. Afterwards, the improved method is applied to heat diffusion and unidirectional fluid flow simulations. Within t...
Development and validation of two-dimensional depht-averaged free surface flow solver
Yılmaz, Burak; Aydın, İsmail; Department of Civil Engineering (2003)
A numerical solution algorithm based on finite volume method is developed for unsteady, two-dimensional, depth-averaged shallow water flow equations. The model is verified using test cases from the literature and free surface data obtained from measurements in a laboratory flume. Experiments are carried out in a horizontal, rectangular channel with vertical solid boxes attached on the sidewalls to obtain freesurface data set in flows where three-dimensionality is significant. Experimental data contain both ...
Transient simulation of radiating flows
Selçuk, Nevin; Ayranci, I; Tarhan, T (2005-06-01)
Time-dependent Navier-Stokes equations are solved in conjunction with the radiative transfer equation by coupling a previously developed direct numerical simulation-based computational fluid dynamics code to an existing radiation code, both based on the method of lines approach. The temperature profiles predicted by the coupled code are validated against steady-state solutions available in the literature for laminar, axisymmetric, hydrodynamically developed flow of a gray, absorbing, emitting fluid in a hea...
Modeling and numerical analysis of single droplet drying
Dalmaz, Nesip; Özbelge, H. Önder; Department of Chemical Engineering (2005)
A new single droplet drying model is developed that can be used as a part of computational modeling of a typical spray drier. It is aimed to describe the drying behavior of a single droplet both in constant and falling rate periods using receding evaporation front approach coupled with the utilization of heat and mass transfer equations. A special attention is addressed to develop two different numerical solution methods, namely the Variable Grid Network (VGN) algorithm for constant rate period and the Vari...
Citation Formats
A. E. Dinçer, “Numerical investigation of free surface and pipe flow problems by smoothed particle hydrodynamics,” Ph.D. - Doctoral Program, Middle East Technical University, 2017.