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domain-decomposition
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Performing building vibration assessments by acoustic measurements
, Article Building Acoustics ; Volume 27, Issue 1 , December , 2020 , Pages 21-33 ; Peplow, A ; Kasaei, A ; Sharif University of Technology
SAGE Publications Inc
2020
Abstract
This article presents an innovative application of the frequency domain decomposition method based on an acoustic and vibration response. Frequency domain decomposition method has been frequently used for operational modal analysis testing in the last decade to identify modal parameters for in-situ case studies. For these studies, the outputs of the vibration response through accelerometers have been employed in the analysis. In this article, the frequency domain decomposition method is employed, for the first time, to analyze both acoustic and vibration response of the building which is a novel application in building vibration response. As a case study, a cylindrical shaped seven-story...
A new parallel Gauss-Seidel method based on alternating group explicit method and domain decomposition method
, Article Applied Mathematics and Computation ; Volume 188, Issue 1 , 2007 , Pages 713-719 ; 00963003 (ISSN) ; Davami, P ; Sharif University of Technology
2007
Abstract
A new parallel Gauss-Seidel method is presented for solution of system of linear equations related to finite difference discretization of partial differential equations. This method is based on domain decomposition method and local coupling between interfaces of neighbor sub-domains, same as alternating group explicit method. This method is convergent and number of iterations for achieving convergence criteria is near the original Gauss-Seidel method (sometimes better and sometimes worse but difference is very small). The convergence theory is discussed in details. Numerical results are given to justify the convergence and performance of the proposed iterative method. © 2006 Elsevier Inc....
Parallel Simulation of Generalized Newtonian Flows Using Smoothed Particle Hydrodynamics
, M.Sc. Thesis Sharif University of Technology ; Taghizade Manzari, Mehrdad (Supervisor)
Abstract
Smoothed Particle Hydrodynamics(SPH) is the oldest Lagrangian method for solving fluid equations. Fluid is approximated with particles that represent a control mass and carry physical properties su as mass, temprature and . . . Simpler formulation relative to other methods like finite volume and finite element, no need for surface traing and ease of adding new physics are benefits of this method. In this method it is necessary to find neighboring particles that are closer than smoothing lenght (h) for ea particle. is is a time consuming operation causing SPH to be a computationaly expensive method. First simulation of Power-law fluids is considered. It has been observed that using of...
Computational Simulation of a Sonic Jet into a Supersonic Cross Flow, Using Parallel Computing
, M.Sc. Thesis Sharif University of Technology ; Rahni, Taeibi (Supervisor)
Abstract
Today’s Missiles are very maneuverable and to increase this ability, side jets are used. Beneficial usages of such systems are in fast responding and more accuracy in response of forces and moments to change directions. In jet in cross flow interactions, boundary layer is separated in front of the jet creating horseshoe vortices plus compression and expansion waves. In this research, we have developed a CFD code to simulate this flow, using the Spalart-Allmaras turbulence model and parallel computing. Then, we have studied the influence of free stream Mach number and momentum ratio. In this simulation, 2 million nodes were used in the computational domain. Also parallel processing with...
A fast method for numerical simulation of casting solidification
, Article Communications in Numerical Methods in Engineering ; Volume 24, Issue 12 , October , 2008 , Pages 1723-1740 ; 10698299 (ISSN) ; Davami, P ; Sharif University of Technology
2008
Abstract
An efficient numerical method for simulation of casting solidification is presented. The presented method is based on a stable explicit finite difference solution of the heat equation in conjunction with the temperature recovery method to incorporate latent heat effect. The computational cost of the presented method is approximately the same as an explicit method (per time step), while it is free from the time step limitation due to the stability criterion. A simple domain decomposition method is included to improve the computational performance of the presented method. The efficiency, stability and accuracy of the presented method are supported with illustrative examples. Copyright © 2007...
Investigation of continuous-time quantum walk by using Krylov subspace-Lanczos algorithm
, Article European Physical Journal B ; Volume 59, Issue 2 , 2007 , Pages 199-216 ; 14346028 (ISSN) ; Sufiani, R ; Salimi, S ; Jafarizadeh, S ; Sharif University of Technology
2007
Abstract
In papers [Jafarizadehn and Salimi, Ann. Phys. 322, 1005 (2007) and J. Phys. A: Math. Gen. 39, 13295 (2006)], the amplitudes of continuous-time quantum walk (CTQW) on graphs possessing quantum decomposition (QD graphs) have been calculated by a new method based on spectral distribution associated with their adjacency matrix. Here in this paper, it is shown that the CTQW on any arbitrary graph can be investigated by spectral analysis method, simply by using Krylov subspace-Lanczos algorithm to generate orthonormal bases of Hilbert space of quantum walk isomorphic to orthogonal polynomials. Also new type of graphs possessing generalized quantum decomposition (GQD) have been introduced, where...
2D parallel and stable group explicit finite difference method for solution of diffusion equation
, Article Applied Mathematics and Computation ; Volume 188, Issue 2 , 2007 , Pages 1184-1192 ; 00963003 (ISSN) ; Davami, P ; Sharif University of Technology
2007
Abstract
Recently various versions of alternating group explicit or alternating group explicit-implicit methods were proposed for solution of diffusion equation. The main benefits of these methods are: good stability, accuracy and parallelizing. But these methods were developed for 1D case and stability and accuracy were investigated for 1D case too. In the present study we extend the new group explicit method [R. Tavakoli, P. Davami, New stable group explicit finite difference method for solution of diffusion equation, Appl. Math. Comput. 181 (2006) 1379-1386] to 2D with operator splitting method. The implementation of method is discussed in details. Our numerical experiment shows that such 2D...
New stable group explicit finite difference method for solution of diffusion equation
, Article Applied Mathematics and Computation ; Volume 181, Issue 2 , 2006 , Pages 1379-1386 ; 00963003 (ISSN) ; Davami, P ; Sharif University of Technology
2006
Abstract
A new group explicit method for solution of diffusion equation is presented. This method is based on domain decomposition concept and using asymmetric Saul'yev schemes for internal nodes of each sub-domain and alternating group explicit method for sub-domain's interfacial nodes. This new method has several advantages such as: good parallelism, unconditional stability, fully explicit nature and better accuracy than original Saul'yev schemes. The details of implementation and proving stability are briefly discussed. Numerical experiments on stability and accuracy are also presented. © 2006 Elsevier Inc. All rights reserved
Damage Detection of Offshore Jacket Platforms Using Fitting Vibration Data
, M.Sc. Thesis Sharif University of Technology ; Ali Akbar, Golafshani (Supervisor)
Abstract
In the regard of structural health monitoring the identification of the structural modal parameters is essential. Since the different sources (wind, waves, Devices …) induce vibration on an offshore platform, it is impossible to determine the portion of each source in vibration. Thus the methods that analyze vibrations needless of input measurements are more efficient. These methods apply the ambient factors and obtain the modal properties from the structural response. This procedure has no unwanted effect on the serviceability of structure and by placement of sensors on the platform; one can monitor the structural health.
In the present work a two dimensional jacket offshore platform...
In the present work a two dimensional jacket offshore platform...
Response Simulation of Non-Classically Damped Structures using Modal and Stochastic Subspace Identification
, M.Sc. Thesis Sharif University of Technology ; Ahmadizadeh, Mehdi (Supervisor)
Abstract
As more structures are equipped with supplemental energy dissipation devices, the assumption of classical damping becomes less accurate. For this reason, development of a general identification method that is accurate enough for response simulation is emparative for such structures. Modal identification of structures can be carried out using either modal or state space approach. In modal methods (such as wavelet transform method), the damping matrix needs to be identified for response simulation. This is sometimes difficult, and may result in simulation inaccuracies. In contrast, direct identification of damping matrix for simulation is not required in state space approach. Hence, the...