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In this manuscript, we will apply the regularized meshless method, coupled with an error estimation technique, to tackle the challenge of modeling oblique incident waves interacting with multiple cylinders. Given the impracticality of obtaining an exact solution in many real engineering problems, we introduce an error estimation technique designed to achieve reliable solutions. This technique excels in providing dependable solutions that closely approximate analytical solutions. An additional advantage is its capacity to identify the optimal number of points for both source and collocating points, thereby enhancing computational efficiency. The validity of the proposed method will be demonstrated through three numerical cases, presenting results that exhibit substantial agreement. [ABSTRACT FROM AUTHOR]

In this manuscript, we will apply the regularized meshless method, coupled with an error estimation technique, to tackle the challenge of modeling oblique incident waves interacting with multiple cylinders. Given the impracticality of obtaining an exact solution in many real engineering problems, we introduce an error estimation technique designed to achieve reliable solutions. This technique excels in providing dependable solutions that closely approximate analytical solutions. An additional advantage is its capacity to identify the optimal number of points for both source and collocating points, thereby enhancing computational efficiency. The validity of the proposed method will be demonstrated through three numerical cases, presenting results that exhibit substantial agreement.

The problem of reflection of longitudinal and transverse waves from the boundary of a half-plane is considered. It is assumed that boundary conditions are a generalization the sliding contact and assume that the tangential stresses do not vanish, but obey the law of dry friction. Analytical expressions are obtained for the ratios of the amplitudes of reflected waves to the amplitude of an incident longitudinal or transverse wave. A numerical analysis of the dependence of these ratios on the wave incidence angle, friction coefficient, and Poisson's ratio is carried out. It is shown that when the direction of the boundary shear stresses and the direction of propagation of the incident both longitudinal and transverse waves coincide, there are critical angles of incidence at which the amplitudes of the reflected waves become infinite. [ABSTRACT FROM AUTHOR]

An inverse unsteady boundary value problem of a plane oblique pressure wave diffraction on a convex surface in the form of a parabolic cylinder is considered. At the same time, approximate models of the interaction of a wave with a rigid obstacle in a liquid are constructed, based on the hypothesis of a thin layer, which makes it possible to obtain fundamental solutions in a closed-form. To obtain an analytical solution for the direct problem, a non-stationary diffraction problem for an acoustic medium is solved using the transient function of the obstacle surface influence. The operational method is used. In the inverse problem, the angle of the front of the oblique wave is determined based on the measured pressure in the reflected and incident waves on the body surface using the least squares method. Among the results of the study, an algorithm was proposed for solving the inverse boundary value problem of diffraction of a plane oblique pressure wave on a rigid obstacle in the form of a parabolic cylinder by determining the angle of the oblique wave front. [ABSTRACT FROM AUTHOR]

If the octet truss core, which is a space filling structure of half regular octahedrons and regular tetrahedrons, has excellent sound insulation characteristics, the possibility of using the octet truss core is sufficiently widened. From this fact, we have studied to obtain sound insulation characteristics of the flat plate and the plate with single core using acoustic tube by the finite element method (FEM) with high accuracy. The calculation of sound insulation performance by FEM was limited to the qualitative study so far. For example, the correction is required due to the difference from the theoretical value, and the magnitudes of the correction values differ depending on the test pieces. In this study, we considered the incident wave and compared the sound insulation calculation result by the FEM calculation using the non-reflective boundary at the rear end of the sound receiving room with the theoretical calculation. As a result, both calculation values were almost the same. Therefore, it can be said that when the magnitudes of the incident wave and the reflective wave are almost equal, a quantitative study is possible. Taking advantage of this fact, in this paper the sound insulation characteristics of the plate with single core are compared with that of flat plate, and the effects of the sound insulation characteristics by the aspect ratio of the core are examined.

We analyze the Sommerfeld solution to the stationary diffraction by a half‐plane. We prove that this solution is the limiting amplitude for time‐dependent scattering of incident plane waves with a broad class of the profile functions. We also show that this solution is the asymptotics of the limiting amplitudes of solutions to time‐dependent scattering problem with narrow wedges when the angle of the wedge tends to zero. [ABSTRACT FROM AUTHOR]

The authors report a waveform‐selective metasurface that operates at 2.4 GHz band, i.e. one of ISM (Industrial, Scientific and Medical) bands. This structure gives us an additional degree of freedom to control electromagnetic waves and absorbs a particular waveform or pulse width of an incident wave at the same frequency band, while transmitting others. This unique capability is demonstrated using either ideal sinusoidal waves or Wi‐Fi signals as a more practical waveform in wireless communications. Especially, this Letter shows how the waveform‐selective metasurface interacts with realistic wireless communication signals from the viewpoint of communication characteristics, such as error vector magnitude, bit error rate, and phase error. Thus, the authors' Letter paves the way for extending the concept of waveform selectivity from a fundamental electromagnetic research field to a more realistic wireless communication field to, for instance mitigate electromagnetic interference occurring at the same frequency band without significantly degrading communication characteristics. [ABSTRACT FROM AUTHOR]

One of the most promising wave energy converter type is Oscillating Water Column (OWC) system. Fluctuation amounts and the motion behavior of the water column inside the chamber are very important parameters effecting the energy extraction. Therefore, predicting these parameters with respect to varying wave characteristics and geometric design parameters is of great importance. In this study, physical experiments are conducted for a bottom-fixed OWC system with seven different sizes of opening heights under various regular wave series. Average fluctuations inside the chamber are measured. It is found that there is a critical relative opening height ratio (α) that makes the fluctuations maximum regardless of wave parameters used. Exponential and linear relationships are found between average fluctuations and dimensionless parameters ‘dimensionless wave frequency’ and ‘captured wavelength’ defined, respectively. Mathematical models are developed to predict water column fluctuations under varying relative opening heights and wave parameters. The results of mathematical models indicated good aggrement with experimental data. Also chamber water surface profiles are observed and related to defined dimensionless wave parameters. Another factor (named as excessive harmful energy) is determined which also induces sloshing motion inside the chamber after the critical ratio value α is exceeded. It is found that under all wave series, the highest relative average column water surface fluctuations occur at relative opening height α is equal to 0.67 which is a unique value. It can be concluded that mathematical models can be used to estimate water column fluctuations from relative opening height and wave parameter data in the chamber. [ABSTRACT FROM AUTHOR]