Showing 4 results for Harmonic
R. Keypour, H. Seifi, A. Yazdian,
Volume 21, Issue 1 (7-2002)
Abstract
In this paper, two algorithms have been developed for allocation and size determination of Active Power Filters (APF) in power systems. In the first algorithm, the objective is to minimize harmonic voltage distortion. The objective in the second algorithm is to minimize the new APF injection currents while satisfying harmonic standards. Genetic algorithm is proposed for these two optimization problems. The simulation results for an 18-bus system show the effectiveness of the genetic algorithm for these two optimization problems.
Keywords: Genetic Algorithm, Active Power Filter, Harmonics, Allocation, Optimization
F. Mossaiby, M. Nasr Esfahani,
Volume 34, Issue 2 (1-2016)
Abstract
: Existence of singular points inside the solution domain or on its boundary deteriorates the accuracy and convergence rate of numerical methods. This phenomenon usually happens due to discontinuities in the boundary conditions or abrupt changes in the domain shape. This study has focused on the solution of singular plate problems using the exponential basis functions method. In this method, unknown functions are considered as a linear combination of exponential basis functions and the coefficients are calculated by approximate satisfaction of the boundary conditions. To increase the accuracy and convergence rate in problems with singular points, a series of singular, quasi-exponential functions are added to the method’s exponential basis functions. These functions have proper discontinuity in location of the singular points and satisfy the homogenous differential equation. The results obtained from the solution of three cracked plate problems show considerable increase in the accuracy and convergence rate of the proposed method compared with the exponential basis functions method without any noticeable increase in the computational cost.
S. M. Zandi, A. Rafizadeh,
Volume 37, Issue 1 (9-2018)
Abstract
In this article, a meshless method based on exponential basis functions (EBFs) is presented to simulate the harmonic waves with moving free-surfaces generated by the piston-type wave maker. Accordingly, velocity potential is adopted in a Mixed Eulerian-Lagrangian (MEL) approach. Boundary conditions are met through a point-wise collocation approach. In order to update the geometry in the simulation time, the free surface points are only moved vertically. To reduce the reflection in the wave flume, a damping zone is added at the far end opposite to the wave maker, where the velocity is modified by adding an artificial damping term. The results indicated the ability of this numerical method in simulating free surface flow problems like non-linear waves with a good accuracy, as well as suitable performances and the least run time calculation.
O. Bateniparvar, N. Noormohammadi, A. M. Salehi,
Volume 39, Issue 2 (2-2021)
Abstract
In this paper, Equilibrated Singular Basis Functions (EqSBFs) are implemented in the framework of the Finite Element Method (FEM), which can approximately satisfy the harmonic PDE in homogeneous and heterogeneous media. EqSBFs are able to automatically reproduce the terms consistent with the singularity order in the vicinity of the singular point. The newly made bases are used as the complimentary enriching part along with the polynomial bases of the FEM to construct a new set of shape functions in the elements adjacent to the singular point. It will be shown that the use of the combined bases leads to the quality improvement of the solution function as well as its derivatives, especially in the vicinity of the singularity.
