scholarly journals An Optimized Symmetric WENO Method-Based Numerical Simulation of Intense Sound Field Generated by Underwater Plasma Sound Source

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Kaizhuo Lei ◽  
Xiaolong Liu ◽  
Ning Li ◽  
Xuchao Fan
Keyword(s):  
Euler Equations ◽  
Sound Source ◽  
Sound Field ◽  
Maximum Error ◽  
Numerical Examples ◽  
Weighted Essentially Nonoscillatory ◽  
The Third ◽  
Calculation Results ◽  
Pulse Sound ◽  
Fifth Order

The intensive pulse sound wave can be generated by the underwater plasma sound source (UPSS) based on the discharge of the underwater high voltage. The distribution of the sound field is prominently nonlinear. In this paper, the sound field of the intensive UPSS is described by the integral two-dimensional axisymmetric unsteady Euler equations firstly. In order to solve the Euler equations numerically, an optimized fifth-order symmetric WENO (weighted essentially nonoscillatory) method based on the three templates is proposed which is called WENO-SYM3. Without increasing the number of candidate templates, a new symmetric template structure can be obtained by expanding the second template and shifting the third one backwards for one space. The method is validated through numerical examples and experiments, and the results show that WENO-SYM3 has a high distinguished accuracy; meanwhile, its nonphysical oscillations are not obvious. The experimental results are basically the same as the calculation results, and the maximum error is around 3%.

A new type of finite difference WENO schemes for Hamilton–Jacobi equations

2019 ◽  
Vol 30 (02n03) ◽  
pp. 1950020 ◽  
Author(s):  
Xiaohan Cheng ◽  
Jianhu Feng ◽  
Supei Zheng ◽  
Xueli Song
Keyword(s):  
Finite Difference ◽  
Weno Schemes ◽  
Numerical Examples ◽  
Weighted Essentially Nonoscillatory ◽  
New Type ◽  
Spurious Oscillations ◽  
Symmetry Requirement ◽  
Finite Difference Weno Schemes ◽  
Jacobi Equations ◽  
Fifth Order

In this paper, we propose a new type of finite difference weighted essentially nonoscillatory (WENO) schemes to approximate the viscosity solutions of the Hamilton–Jacobi equations. The new scheme has three properties: (1) the scheme is fifth-order accurate in smooth regions while keep sharp discontinuous transitions with no spurious oscillations near discontinuities; (2) the linear weights can be any positive numbers with the symmetry requirement and that their sum equals one; (3) the scheme can avoid the clipping of extrema. Extensive numerical examples are provided to demonstrate the accuracy and the robustness of the proposed scheme.

scholarly journals Fifth-Order Mapped Semi-Lagrangian Weighted Essentially Nonoscillatory Methods Near Certain Smooth Extrema

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Lang Wu ◽  
Dazhi Zhang ◽  
Boying Wu ◽  
Xiong Meng
Keyword(s):  
Finite Difference ◽  
Finite Volume ◽  
Interpolation Scheme ◽  
Numerical Examples ◽  
Weighted Essentially Nonoscillatory ◽  
Accuracy Test ◽  
A Cell ◽  
Fifth Order ◽  
Cell Average ◽  
Essentially Nonoscillatory

Fifth-order mapped semi-Lagrangian weighted essentially nonoscillatory (WENO) methods at certain smooth extrema are developed in this study. The schemes contain the mapped semi-Lagrangian finite volume (M-SL-FV) WENO 5 method and the mapped compact semi-Lagrangian finite difference (M-C-SL-FD) WENO 5 method. The weights in the more common scheme lose accuracy at certain smooth extrema. We introduce mapped weighting to handle the problem. In general, a cell average is applied to construct the M-SL-FV WENO 5 reconstruction, and the M-C-SL-FD WENO 5 interpolation scheme is proposed based on an interpolation approach. An accuracy test and numerical examples are used to demonstrate that the two schemes reduce the loss of accuracy and improve the ability to capture discontinuities.

scholarly journals Decay of Non-Diffuse Sound Fields in a Room

2020 ◽  
Vol 320 ◽  
pp. 00006
Author(s):  
Alena Novoselova ◽  
Nikolay Kanev
Keyword(s):  
Sound Source ◽  
Relative Position ◽  
Sound Field ◽  
Strong Anisotropy ◽  
Sound Fields ◽  
The Third ◽  
Field Diffusion ◽  
Absorbing Material ◽  
Field Decay ◽  
Exponential Power

The paper presents the results of a study of a non-diffuse sound field decay in a room. In a laboratory experiment, a model of a room in the form of a rectangular parallelepiped with a size of 0.7 x 0.4 x 0.4 m is used. Two non-parallel walls are coated with sound absorbing material. Sound scattering elements can be placed on the third wall which is perpendicular to the absorbing ones, which allows to change the field diffusion degree. The sound field in such a room has a strong anisotropy, its energy decays according to the exponential-power law. Sound decay curves were measured at various positions of the sound source and microphone at frequencies of 4 kHz. The decay curves are compared, their dependence on the relative position of the sound source and microphone is analyzed.

scholarly journals Reputasi Universitas, Biaya Kuliah, Fasilitas Perkuliahan dan Keputusan Mahasiswa Memilih Program Studi Manajemen Universitas Flores: Studi Pada Mahasiswa Program Studi Manajemen Angkatan 2019

Analisis ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 104-117
Author(s):  
Yosafat Kristianus Bao ◽  
Maria Helena Carolinda Dua Mea
Keyword(s):  
Quantitative Approach ◽  
Research Approach ◽  
Study Program ◽  
Significance Level ◽  
Management Study ◽  
The Third ◽  
Calculation Results ◽  
The University ◽  
Tuition Costs

The decision to study in a major is a big challenge among most students. They will consider the existing conditions or circumstances. If the circumstances or conditions seem not in accordance with what is expected, there will be doubts which result in the decision not to choose the expected study program. Although in making a decision to take education in a study program, a consideration is needed, however, students of the Management study program have not conducted an analysis of the study program they are taking. The research approach used is a quantitative approach. From the calculation, the t-count value is 19.794 with a significance level of 0.000 or a sig value <0.05, the first hypothesis which states "the reputation of the university affects the student's decision to choose Management Study Program at the University of Flores" is accepted. From the calculation results, the t-count value is 0.887 with a significance level of 0.377 or sig> 0.05, thus the second hypothesis which states "tuition costs affect students' decisions to choose Management Study Program at the University of Flores" is rejected. From the calculation results, it is obtained that the t-count value is 5.295 with a significance level of 0.000 or a sig value <0.05, the third hypothesis which states "lecture facilities affect the student's decision to choose Management Study Program at the University of Flores" is accepted.

scholarly journals Linearization of symmetrical and asymmetrical two-way Doherty amplifier

2012 ◽  
Vol 25 (2) ◽  
pp. 161-170 ◽  
Author(s):  
Aleksandar Atanaskovic ◽  
Natasa Males-Ilic ◽  
Bratislav Milovanovic
Keyword(s):  
Fourth Order ◽  
Linearization Technique ◽  
The Third ◽  
Simulation Process ◽  
Input And Output ◽  
Carrier Cell ◽  
Fifth Order ◽  
Doherty Amplifier

The linearization effects on two-way Doherty amplifiers are presented in this paper. Symmetrical Doherty amplifier with the additional circuit for linearization has been realized and measurements of the linearization influence on the third- and fifth-order intermodulation products have been carried out. Asymmetrical Doherty amplifier has been designed and effects of the applied linearization technique have been considered through the simulation process. The linearization approach uses the fundamental signals? second harmonics and fourth-order nonlinear signals that are extracted at the output of the peaking cell, adjusted in amplitude and phase and injected at the input and output of the carrier cell in Doherty amplifier.

scholarly journals COMPARISON OF THREE CALCULATION METHODS OF ENERGY PERFORMANCE CERTIFICATES IN SLOVENIA

2018 ◽  
Vol 13 (1) ◽  
Author(s):  
Wadie Kidess
Keyword(s):  
Numerical Calculation ◽  
Energy Performance ◽  
Heat Losses ◽  
Calculation Methods ◽  
The Third ◽  
Simplified Method ◽  
Calculation Results ◽  
Thermal Bridges ◽  
Simplified Calculation ◽  
Family House

In order to get the authorization for issuing energy performance certificates in Slovenia, the expert candidate has to attend the prescribed course and pass the exam. The simplified method for heat losses calculation that is taught at this course neglects the thermal bridges, raising concerns whether the calculation results are reliable. In this paper we have compared three methods for calculation of thermal losses for a “typical” family house. The first is the above mentioned simplified calculation using a correctional factor; the second takes into account the thermal bridges, using linear thermal transmittances obtained by numerical calculation, and the third takes into account the thermal bridges, using default values for linear thermal transmittances. Noting that the second method returns the most exact values, we have found that the first method results are too large, yet still smaller than the third method results.

scholarly journals B-splines Algorithms for Solving Fredholm Linear Integro-Differential Equations

2004 ◽  
Vol 1 (2) ◽  
pp. 340-346
Author(s):  
Baghdad Science Journal
Keyword(s):  
Differential Equations ◽  
Spline Function ◽  
Cubic Spline ◽  
Second Order ◽  
Third Order ◽  
B Spline ◽  
Numerical Examples ◽  
B Splines ◽  
The Third ◽  
New Procedures

Algorithms using the second order of B -splines [B (x)] and the third order of B -splines [B,3(x)] are derived to solve 1' , 2nd and 3rd linear Fredholm integro-differential equations (F1DEs). These new procedures have all the useful properties of B -spline function and can be used comparatively greater computational ease and efficiency.The results of these algorithms are compared with the cubic spline function.Two numerical examples are given for conciliated the results of this method.

Optimization of the Sound Source Position for Shaping Acoustically-Structurally Coupled Cavities

2001 ◽  
Author(s):  
Arzu Gonenc Sorguc ◽  
Ichiro Hagiwara ◽  
Qinzhong Shi ◽  
Haldun Akagunduz
Keyword(s):  
Sound Source ◽  
Sequential Quadratic Programming ◽  
Normal Modes ◽  
Sound Field ◽  
Source Strength ◽  
Source Position ◽  
Sound Sources ◽  
Coupled Cavities ◽  
Structural Loading ◽  
Initial Starting

Abstract In this study, sound field inside acoustically-structurally coupled rectangular cavity excited by structural loading and sound sources is shaped by optimizing the position of the sound source. In the optimization, Most Probable Optimal Design (MPOD) based on Holographic Neural Network is employed and the results are compared with Sequential Quadratic Programming (SQP). It is shown that source position, rather than source strength, is more effective in acoustically controlled modes. The nodal positions for in-vacuo acoustical normal modes are good candidates for initial starting points.

scholarly journals Demonstration of Transmission Mode Soft X-ray NEXAFS Using Third- and Fifth-Order Harmonics of FEL Radiation at SACLA BL1

2020 ◽  
Vol 10 (21) ◽  
pp. 7852
Author(s):  
Hiroshi Iwayama ◽  
Masanari Nagasaka ◽  
Ichiro Inoue ◽  
Shigeki Owada ◽  
Makina Yabashi ◽  
...  
Keyword(s):  
Fine Structure ◽  
Free Electron ◽  
Free Electron Laser ◽  
Transmission Mode ◽  
Pump Probe ◽  
X Ray ◽  
The Third ◽  
Nexafs Spectroscopy ◽  
Fifth Order ◽  
X Ray Absorption

We demonstrate the applicability of third- and fifth-order harmonics of free-electron laser (FEL) radiation for soft X-ray absorption spectroscopy in the transmission mode at SACLA BL1, which covers a photon energy range of 20 to 150 eV in the fundamental FEL radiation. By using the third- and fifth-order harmonics of the FEL radiation, we successfully recorded near-edge X-ray absorption fine structure (NEXAFS) spectra for Ar 2p core ionization and CO2 C 1s and O 1s core ionizations. Our results show that the utilization of third- and fifth-order harmonics can significantly extend the available photon energies for NEXAFS spectroscopy using an FEL and opens the door to femtosecond pump-probe NEXAFS using a soft X-ray FEL.

scholarly journals Semi Implicit Hybrid Methods with Higher Order Dispersion for Solving Oscillatory Problems

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
S. Z. Ahmad ◽  
F. Ismail ◽  
N. Senu ◽  
M. Suleiman
Keyword(s):  
Fourth Order ◽  
Absolute Stability ◽  
Hybrid Methods ◽  
Order Method ◽  
The Third ◽  
Dispersion Order ◽  
Runge Kutta ◽  
Fifth Order ◽  
Higher Order Dispersion ◽  
Order Dispersion

We constructed three two-step semi-implicit hybrid methods (SIHMs) for solving oscillatory second order ordinary differential equations (ODEs). The first two methods are three-stage fourth-order and three-stage fifth-order with dispersion order six and zero dissipation. The third is a four-stage fifth-order method with dispersion order eight and dissipation order five. Numerical results show that SIHMs are more accurate as compared to the existing hybrid methods, Runge-Kutta Nyström (RKN) and Runge-Kutta (RK) methods of the same order and Diagonally Implicit Runge-Kutta Nyström (DIRKN) method of the same stage. The intervals of absolute stability or periodicity of SIHM for ODE are also presented.

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