Browsing by Subject "Mathematical modeling."

Now showing 1 - 3 of 3

Open Access
Particle based modeling and simulation of natural phenomena
(2010) Bayraktar, Serkan
This thesis is about modeling and simulation of fluids and cloth-like deformable objects by the physically-based simulation paradigm. Simulated objects are modeled with particles and their interaction with each other and the environment is defined by particle-to-particle forces. We propose several improvements over the existing particle simulation techniques. Neighbor search algorithms are crucial for the performance efficiency and robustness of a particle system. We present a sorting-based neighbor search method which operates on a uniform grid, and can be parallelizable. We improve upon the existing fluid surface generation methods so that our method captures surface details better since we consider the relative position of fluid particles to the fluid surface. We investigate several alternatives of particle interaction schema (i.e. Smoothed Particle Hydrodynamics, the Discrete Element Method, and Lennard-Jones potential) for the purpose of defining fluid-fluid, fluid-cloth, fluid-boundary interaction forces. We also propose a practical way to simulate knitwear and its interaction with fluids. We employ capillary pressure–based forces to simulate the absorption of fluid particles by knitwear. We also propose a method to simulate the flow of miscible fluids. Our particle simulation system is implement to exploit parallel computing capabilities of the commodity computers. Specifically, we implemented the proposed methods on multicore CPUs and programmable graphics boards. The experiments show that our method is computationally efficient and produces realistic results.
Open Access
Physical simulation of wood combustion by using particle system
(2010) Gürcüoğlu, Gizem
In computer graphics, the most challenging problem is modeling natural phenomena such as water, re, smoke etc. The reason behind this challenge is the structural complexity, as the simulation of natural phenomena depends on some physical equations that are di cult to implement and model. In complex physically based simulations, it is required to keep track of several properties of the object that participates in the simulation. These properties can change and their alteration may a ect other physical and thermal properties of object. As one of natural phenomena, burning wood has various properties such as combustion reaction, heat transfer, heat distribution, fuel consumption and object shape in which change in one during the duration of simulation alters the e ects of some other properties. There have been several models for animating and modeling re phenomena. The problem with most of the existing studies related to re modeling is that decomposition of the burning solid is not mentioned, instead solids are treated only as fuel source. In this thesis, we represent a physically based simulation of a particle based method for decomposition of burning wood and combustion process. In our work, besides being a fuel source, physical and thermal a ects of combustion process over wood has been observed. A particle based system has been modelled in order to simulate the decomposition of a wood object depending on internal and external properties and their interactions and the motion of the spreading re according to combustion process.
Open Access
Physically-based animation of elastically deformable models
(1994) Güdükbay, Uğur
Although kinematic modeling methods are adequate for describing the shapes of static objects, they are insufficient when it comes to producing realistic animation. Physically-based modeling remedies this problem by including forces, masses, strain energies, and other physical quantities. The behavior of physicallybased models is governed by the laws of rigid and nonrigid dynamics expressed through a set of equations of motion. In this thesis, we describe a system for the animation of deformable models. A spring force formulation for animating deformable models is also presented. The animation system uses the physicallybased modeling methods and the approaches from elasticity theory for animating the models. Three different formulations, namely the primal, hrjhrid, and the spring force formulations, are implemented so that the user could select the suitable one for an animation, considering the advantages and disadvantages of each formulation. Collision of the models with impenetrable obstacles and constraining model points to fixed positions iii space are implemented.