The two-dimensional problem of acoustic scattering of an incident plane wave by a semi-infinite array of either rigid or soft circular scatterers is solved. Solutions to the corresponding infinite array problems are used, together with a novel filtering approach, to enable accurate solutions to be computed efficiently. Particular attention is focussed on the determination of the amplitude of th...

In a series of papers Amati, Ciafaloni and Veneziano and 't Hooft conjectured that black holes occur in the collision of two light particles at planckian energies. In this paper we discuss a possible scenario for such a process by using the Chandrasekhar-Ferrari-Xanthopoulos duality between the Kerr black hole solution and colliding plane gravitational waves. We clarify issues arising in the de...

Spinodal decomposition is a phase-separation phenomenon occurring at non-equilibrium conditions. In isotropic materials, it is expected to improve the physical properties, in which modulated structures arise from a single system of spinodal waves. However, in anisotropic materials this process is controversial and not very well understood. Here, we report anisotropic spinodal decomposition patt...

is derived for surface gravity waves with nearly-elliptic front, generalising the cylindrical KP equation for nearly-concentric waves. We discuss transformations between the derived equation and two existing versions of the KP equation, for nearly-plane and nearly-concentric waves. The transformations are used to construct important classes of exact solutions of the derived equation and corresp...

The present investigation is to study the surface waves propagation with imperfect boundary between an isotropic elastic layer of finite thickness and a homogenous isotropic thermodiffusive elastic half- space with rotation in the context of Green-Lindsay (G-L model) theory. The secular equation for surface waves in compact form is derived after developing the mathematical model. The phase velo...

In the theories of electrodynamics, acoustics, and optics, fields that satisfy the homogeneous wave equation are often represented by integral expansions of monochromatic plane waves, all propagating with the same speed [ 1,2] . Two different plane-wave expansions are in use. One expansion, due to Whittaker [3] , expresses the field as a superposition of monochromatic, homogeneous plane waves; ...

We present a dynamically tunable mechanism of wave transmission in one-dimensional helicoidal phononic crystals in a shape similar to DNA structures. These helicoidal architectures allow slanted nonlinear contact among cylindrical constituents, and the relative torsional movements can dynamically tune the contact stiffness between neighboring cylinders. This results in cross-talking between in-...

This problem was first discussed by Stokes over 150 years ago [1, 2, 3, 4], who noted that three-dimensional sound waves from a bounded source cannot be unipolar. While his argument applies to electromagnetic waves as well, this is little recognized in the literature. One-dimensional electromagnetic (and sound) waves can be unipolar. A plane wave can have any pulseform, but, strictly speaking, ...

lens is specified for tr-msitioning plane waves betwe " an media of specified is desired to have the plane wave in the second medium propagate .. .-.' " ~~ to the assumed plane boundary of that medium. The results for the case of normal. 'scide~ce are then gended to the c~ase of non-normal incidence. In particuk, the. ' '2@tions of tit the conservation and imptyhnce matching are related to the ...

Reflection and transmission of plane waves between two initially stressed thermoelastic half-spaces with orthotropic type of anisotropy is studied. Incidence of a SV-type wave from the lower half-space is considered and the amplitude ratios of the reflected and transmitted SV-wave, P-wave and thermal wave are obtained by using appropriate boundary conditions. Numerical computation for a particu...