Numerical study of random variations of span lengths and span path-average dispersions on dispersion-managed soliton system performance

2003 ◽  
Vol 21 (3) ◽  
pp. 769-775 ◽  
Author(s):  
Chongjin Xie ◽  
L.F. Mollenauer ◽  
N. Mamysheva
Keyword(s):  
System Performance ◽  
Numerical Study ◽  
Dispersion Managed Soliton

scholarly journals Performance Assessment of a Triangular Integrated Collector Using Neural Networks

2020 ◽  
Vol 10 (1) ◽  
pp. 175-181
Author(s):  
Omer K. Ahmed ◽  
Raid W. Daoud ◽  
Ruaa H. Ali Al-Mallah
Keyword(s):  
System Performance ◽  
Solar Collector ◽  
Numerical Study ◽  
Operating Period ◽  
Ansys Fluent ◽  
Test Conditions ◽  
Backpropagation Network ◽  
Optimum Geometry ◽  
Internal Partition ◽  
Fluent Software

A numerical study is achieved on a new shape of temperature saver solar collector using an artificial neural network. The storage collector is a triangle face and a right triangle pyramid for the volumetric shape. It is obtained by cutting a cube from one upper corner at 45°, down to the opposite hypotenuse of the base of the cube. The numerical study was carried out using the computational fluid dynamics code (ANSYS-Fluent) software with natural convection phenomenon in the pyramid enclosure. Elman backpropagation network is used for his ability to find the nearest solution with the smallest error rate. The network consists of three layers, each of different corresponding weights. The results show that the temperature and velocity distributions throughout the operating period were obtained. The influence of introducing an internal partition inside the triangular storage collector was investigated. Also the optimum geometry and location for this partition were obtained. The enhancement was best at y = 0.25 m, whereas the height of triangular collector was 0.5 m. The hourly system performance was evaluated for all test conditions. The performance of the NN to train a model for this work was 0.000207, while the error of the calculation was 1×10-2 as average.

Stabilizing Sequence Search for Time-Controlled Switched Nonlinear Systems with All Unstable Modes

2018 ◽  
Vol 18 (06) ◽  
pp. 1871007
Author(s):  
Jiqiang Wang
Keyword(s):  
Switched Systems ◽  
System Performance ◽  
Numerical Study ◽  
Time Sequence ◽  
Duty Ratio ◽  
Switching Frequency ◽  
Switched Nonlinear Systems ◽  
Fast Switching ◽  
Sequence Search ◽  
Switching Method

One of the important problems in time-controlled switched dynamical systems is to find a stabilizing time sequence if there is any. The problem is challenging for switched systems with all unstable modes. Two fundamental approaches are introduced, which are classified as the fast switching method and the method of converting state-controlled signals. Five schemes are delineated and validated in the numerical study based on the two approaches. The effects of switching frequency and duty ratio on the dynamical system performance are analyzed, from which important implications have been drawn for use in practical system design. The proposed methods shall also provide intuition into understanding the mechanism of how to maintain a dynamical system’s stability when all of its modes are unstable.

scholarly journals Numerical study of propulsion system performance during ship acceleration

2018 ◽  
Vol 149 ◽  
pp. 383-396 ◽  
Author(s):  
P. Mizythras ◽  
E. Boulougouris ◽  
G. Theotokatos
Keyword(s):  
System Performance ◽  
Numerical Study ◽  
Propulsion System

Numerical study of the low-frequency atomic dynamics in a Lennard-Jones glass

1998 ◽  
Vol 77 (2) ◽  
pp. 473-484 ◽  
Author(s):  
M. Sampoli, P. Benassi, R. Dell'Anna,
Keyword(s):  
Numerical Study ◽  
Low Frequency ◽  
Lennard Jones
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