scholarly journals Wave interaction with two-dimensional bodies floating in a two-layer fluid: uniqueness and trapped modes

2003 ◽  
Vol 490 ◽  
pp. 321-331 ◽  
Author(s):  
N. KUZNETSOV ◽  
M. MCIVER ◽  
P. MCIVER
Keyword(s):  
Wave Interaction ◽  
Two Dimensional ◽  
Trapped Modes

scholarly journals Trapped modes in a waveguide with a long obstacle

2000 ◽  
Vol 403 ◽  
pp. 251-261 ◽  
Author(s):  
N. S. A. KHALLAF ◽  
L. PARNOVSKI ◽  
D. VASSILIEV
Keyword(s):  
Two Dimensional ◽  
Trapped Modes ◽  
Acoustic Waveguide ◽  
Trapped Mode ◽  
Rectangular Obstacle

Consider an infinite two-dimensional acoustic waveguide containing a long rectangular obstacle placed symmetrically with respect to the centreline. We search for trapped modes, i.e. modes of oscillation at particular frequencies which decay down the waveguide. We provide analytic estimates for trapped mode frequencies and prove that the number of trapped modes is asymptotically proportional to the length of the obstacle.

Dissipation Improvement of MUSCL Scheme for Computational Aeroacoustics

2001 ◽  
Vol 17 (1) ◽  
pp. 39-47
Author(s):  
San-Yin Lin ◽  
Sheng-Chang Shih ◽  
Jen-Jiun Hu
Keyword(s):  
Wave Interaction ◽  
Sine Wave ◽  
Numerical Dissipation ◽  
Finite Volume Scheme ◽  
Linear Wave ◽  
Riemann Solver ◽  
Two Dimensional ◽  
Order Accuracy ◽  
Upwind Schemes ◽  
Continuous Waves

ABSTRACTAn upwind finite-volume scheme is studied for solving the solutions of two dimensional Euler equations. It based on the MUSCL (Monotone Upstream Scheme for Conservation Laws) approach with the Roe approximate Riemann solver for the numerical flux evaluation. First, dissipation and dispersion relation, and group velocity of the scheme are derived to analyze the capability of the proposed scheme for capturing physical waves, such as acoustic, entropy, and vorticity waves. Then the scheme is greatly enhanced through a strategy on the numerical dissipation to effectively handle aeroacoustic computations. The numerical results indicate that the numerical dissipation strategy allows that the scheme simulates the continuous waves, such as sound and sine waves, at fourth-order accuracy and captures the discontinuous waves, such a shock wave, sharply as well as most of upwind schemes do. The tested problems include linear wave convection, propagation of a sine-wave packet, propagation of discontinuous and sine waves, shock and sine wave interaction, propagation of acoustic, vorticity, and density pulses in an uniform freestream, and two-dimensional traveling vortex in a low-speed freestream.

Numerical Simulation of Non-Gaussian Wave Elevation and Kinematics Based on Two-Dimensional Fourier Transform

2006 ◽  
Author(s):  
Xiang Yuan Zheng ◽  
Torgeir Moan ◽  
Ser Tong Quek
Keyword(s):  
Fourier Transform ◽  
Wave Interaction ◽  
Wave Theory ◽  
Two Dimensions ◽  
Second Order ◽  
Interaction Matrix ◽  
Random Wave ◽  
Two Dimensional ◽  
Near Surface ◽  
Wave Elevation

The one-dimensional Fast Fourier Transform (FFT) has been extensively applied to efficiently simulate Gaussian wave elevation and water particle kinematics. The actual sea elevation/kinematics exhibit non-Gaussianities that mathematically can be represented by the second-order random wave theory. The elevation/kinematics formulation contains double-summation frequency sum and difference terms which in computation make the dynamic analysis of offshore structural response prohibitive. This study aims at a direct and efficient two-dimensional FFT algorithm for simulating the frequency sum terms. For the frequency difference terms, inverse FFT and FFT are respectively implemented across the two dimensions of the wave interaction matrix. Given specified wave conditions, not only the wave elevation but kinematics and associated Morison force are simulated. Favorable agreements are achieved when the statistics of elevation/kinematics are compared with not only the empirical fits but the analytical solutions developed based on modified eigenvalue/eigenvector approach, while the computation effort is very limited. In addition, the stochastic analyses in both time-and frequency domains show that the near-surface Morison force and induced linear oscillator response exhibits stronger non-Gaussianities by involving the second-order wave effects.

A Computationally Efficient Two-Dimensional Model of the Beam–Wave Interaction in a Coupled-Cavity TWT

2012 ◽  
Vol 40 (6) ◽  
pp. 1575-1589 ◽  
Author(s):  
Alexander N. Vlasov ◽  
Thomas M. Antonsen ◽  
Igor A. Chernyavskiy ◽  
David P. Chernin ◽  
Baruch Levush
Keyword(s):  
Wave Interaction ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Computationally Efficient ◽  
Beam Wave ◽  
Two Dimensional Model ◽  
Beam Wave Interaction ◽  
Coupled Cavity

Plasma waves in two-dimensional electron channels: Propagation and trapped modes

2007 ◽  
Vol 14 (4) ◽  
pp. 465-481 ◽  
Author(s):  
B. S. Pavlov ◽  
T. V. Rudakova ◽  
V. I. Ryzhii ◽  
I. A. Semenikhin
Keyword(s):  
Plasma Waves ◽  
Two Dimensional ◽  
Trapped Modes ◽  
Dimensional Electron

A Class of Hybrid DG/FV Methods for Conservation Laws III: Two-Dimensional Euler Equations

2012 ◽  
Vol 12 (1) ◽  
pp. 284-314 ◽  
Author(s):  
Laiping Zhang ◽  
Wei Liu ◽  
Lixin He ◽  
Xiaogang Deng
Keyword(s):  
Euler Equations ◽  
Lower Order ◽  
Wave Interaction ◽  
Weak Shock ◽  
Higher Order ◽  
Two Dimensional ◽  
Dynamic Reconstruction ◽  
Third Order ◽  
Dg Method ◽  
Hybrid Grids

AbstractA concept of “static reconstruction” and “dynamic reconstruction” was introduced for higher-order (third-order or more) numerical methods in our previous work. Based on this concept, a class of hybrid DG/FV methods had been developed for one-dimensional conservation law using a “hybrid reconstruction” approach, and extended to two-dimensional scalar equations on triangular and Cartesian/triangular hybrid grids. In the hybrid DG/FV schemes, the lower-order derivatives of the piece-wise polynomial are computed locally in a cell by the traditional DG method (called as “dynamic reconstruction”), while the higher-order derivatives are re-constructed by the “static reconstruction” of the FV method, using the known lower-order derivatives in the cell itself and in its adjacent neighboring cells. In this paper, the hybrid DG/FV schemes are extended to two-dimensional Euler equations on triangular and Cartesian/triangular hybrid grids. Some typical test cases are presented to demonstrate the performance of the hybrid DG/FV methods, including the standard vortex evolution problem with exact solution, isentropic vortex/weak shock wave interaction, subsonic flows past a circular cylinder and a three-element airfoil (30P30N), transonic flow past a NACA0012 airfoil. The accuracy study shows that the hybrid DG/FV method achieves the desired third-order accuracy, and the applications demonstrate that they can capture the flow structure accurately, and can reduce the CPU time and memory requirement greatly than the traditional DG method with the same order of accuracy.

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