scholarly journals Gyrotron Development at High Order Modes

2021 ◽  
Vol 34 (4) ◽  
pp. 17-25
Author(s):  
Luma Y. Abbas ◽  
Nedal ali Hussain ◽  
Ali N Mohammed
Keyword(s):  
Finite Difference Method ◽  
Thermal Loading ◽  
Interaction Model ◽  
Rf Plasma ◽  
Electron Motion ◽  
Higher Order Modes ◽  
Fortran Language ◽  
The Finite Difference Method ◽  
Operation Frequency ◽  
Good Agreement

      The present work has been characterized by higher order modes in the cavities of the Gyrotron; they are capable of producing RF plasma by developments of it. It uses for fusion systems. We choose the TE31,8 mode in our study. The main problem of gyrotron is the device of the thermal cavity loading. The problem of the thermal loading is solved when any parasitic modes suppress, absence of desired modes; the thermal loading is increased when the high power tube of gyrotron operation is unstable. The mathematical interaction model contains equations that describe the electron motion and the field profiles of the transferred electric modes of the resonator, these are interacting with electrons based on the finite difference method that has been designed to study the starting current, the frequency, quality factor and calculates the roots of the Bessel function by the program we designed in Fortran language. They are used to calculate the operation frequency. Good agreement is between our results and the previous published results both confirm the accuracy of the performance of the designed program.

CROSS-VALIDATION OF NUMERICAL SCHEMES FOR EXTENDED HYDRODYNAMICAL MODELS OF SEMICONDUCTORS

2000 ◽  
Vol 10 (06) ◽  
pp. 833-861 ◽  
Author(s):  
ANGELO MARCELLO ANILE ◽  
MICHAEL JUNK ◽  
VITTORIO ROMANO ◽  
GIOVANNI RUSSO
Keyword(s):  
Finite Difference ◽  
Finite Difference Method ◽  
Cross Validation ◽  
Kinetic Scheme ◽  
Smooth Solutions ◽  
Hydrodynamical Models ◽  
The Finite Difference Method ◽  
Ballistic Diode ◽  
Suitable Modification ◽  
Good Agreement

The numerical integration of the hydrodynamical model of semiconductors based on extended thermodynamics has been tackled. On account of the mathematical complexity of the system, no theoretical conditions of convergence are available for the existing schemes. Therefore in order to obtain numerical solution it was almost mandatory to resort to a cross-validation comparing the results given by two different methods. The kinetic scheme and the finite difference method represented by a suitable modification of the Nessyahu–Tadmor scheme furnish numerical results for the ballistic diode problem in good agreement even for non-smooth solutions.

Transients During a Railway Air Brake Release Demand

1990 ◽  
Vol 204 (1) ◽  
pp. 31-38 ◽  
Author(s):  
M A Murtaza ◽  
S B L Garg
Keyword(s):  
Partial Differential Equations ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Differential Equations ◽  
Difference Method ◽  
Laboratory Data ◽  
One Dimensional ◽  
The Finite Difference Method ◽  
Air Brake System ◽  
Good Agreement

This paper deals with the simulation of railway air brake release demand of a twin-pipe graduated release railway air brake system based on the solution of partial differential equations governing one-dimensional flow by the finite difference method supported by extrapolation/interpolation. Air brake release demand is simulated as an exponential input of pressure. The analysis incorporates the corrections needed to be used for various restrictions in the brake pipeline. Results are in good agreement with the laboratory data.

Vibration Analysis of Helicoidal Plates

1996 ◽  
Vol 210 (6) ◽  
pp. 501-517
Author(s):  
C L Ko
Keyword(s):  
Vibration Analysis ◽  
Natural Frequencies ◽  
Turbine Blades ◽  
Free Vibrations ◽  
Governing Equations ◽  
Higher Order Modes ◽  
Helical Angle ◽  
System Equations ◽  
The Finite Difference Method ◽  
Good Agreement

Governing equations for free vibrations of thin orthotropic or isotropic helicoidal plates are formulated by expressing displacements in terms of components in a helical orthogonal coordinate system. Equations derived for isotropic helicoidal plates are applied to the vibration problem of twisted rectangular turbine blades without camber. These twisted cantilever rectangular blades are simulated to be isotropic helicoidal plates with their angles of twist approximated to be their centre-line helical angles. Natural frequencies are calculated by solving the eigenvalue problem using the finite difference method and are compared to experimental measurements reported in the literature. Reasonably good agreement has been found for flexural modes; however, some discrepancies have also been observed for higher-order modes due to the inaccuracy of modelling the blade geometry as that of a helicoidal plate and due to the approximation of assuming the angle of twist to be the helical angle.

NUMERICAL MODEL TO SIMULATE THE EROSION ON THE SLOPE DUE TO OVERTOPPING

2010 ◽  
Vol 13 (3) ◽  
pp. 78-87
Author(s):  
Hoai Cong Huynh
Keyword(s):  
Numerical Model ◽  
Flow Model ◽  
Bed Load ◽  
Experiment Data ◽  
Step Method ◽  
Morphological Model ◽  
Load Transport ◽  
Bed Load Transport ◽  
The Finite Difference Method ◽  
Good Agreement

The numerical model is developed consisting of a 1D flow model and the morphological model to simulate the erosion due to the water overtopping. The step method is applied to solve the water surface on the slope and the finite difference method of the modified Lax Scheme is applied for bed change equation. The Meyer-Peter and Muller formulae is used to determine the bed load transport rate. The model is calibrated and verified based on the data in experiment. It is found that the computed results and experiment data are good agreement.

Generalized displacement correlation method for mechanical and thermal fracture of FGM

2020 ◽  
Vol 09 (01) ◽  
pp. 2050004
Author(s):  
Y. Ait Ferhat ◽  
A. Boulenouar ◽  
N. Benamara ◽  
L. Benabou
Keyword(s):  
Present Method ◽  
Thermal Loading ◽  
Parametric Design ◽  
Correlation Method ◽  
Functionally Graded ◽  
Mixed Mode Fracture ◽  
Graded Materials ◽  
Displacement Based ◽  
Ansys Parametric Design Language ◽  
Good Agreement

The main objective of this work is to present a numerical modeling of mixed-mode fracture in isotropic functionally graded materials (FGMs), under mechanical and thermal loading conditions. In this paper, the displacement-based method, termed the generalized displacement correlation (GDC) method, is investigated for estimating stress intensity factor (SIF). Using the ANSYS Parametric Design Language (APDL), the continuous variations of the material properties are incorporated by specified parameters at the centroid of each element. This paper presents various numerical examples in which the accuracy of the present method is verified. Comparisons have been made between the SIFs predicted by the GDC method and the available reference solutions in the current literature. A good agreement is achieved between the results of the GDC method and the reference solutions.

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