Extended Spatial Systems

Theoretical Model of Acoustic Wave Propagation in Shallow Water

“…In reality, the sea bottom with properties close to these of the perfectly rigid medium is rather an exception 17,18,19 . At the same time the assumption allowing us to simplify the effects occurring on the water-air boundary is, as a rule, always valid, as the acoustic impedance of water is about 3500 times as high as that of air 13,14 . On the lower boundary of the system, the situation is different, as the acoustic impedance of the sea bottom is typically close to that of water.…”

“…The bottom surface is also determined randomly. Solutions for special cases of this problem can be found in 5,[14][15][16] . The problem of propagation of acoustic disturbances in a medium is usually solved using methods of either wave acoustics or geometrical acoustics.…”

Study of Factors Determinant of Siliceous Electrical Porcelain Resistance to Structural Degradation

“…Velocities of the longitudinal c L and the transverse c T waves, measured along the lengthwise and lateral directions of the insulator, were equal to 5880 and 5750 m/s as well as 3470 m/s and 3390 m/s respectively. Value of Young's modulus E, calculated on the basis of known dependence [9], was equal to 69 and 65 GPa in different directions, at density of the material ρ = 2.31 ± 0.01 g/cm 3 . These values surpass requirements of standards for C 110 type materials -ρ at least 2.20 g/cm 3 and E as a minimum 60 GPa.…”

Modeling and Control of Acoustic Structure Interaction Problems Via Piezoceramic Actuators: 2-D Numerical Examples

“…The velocity potential is determined by the relation i6(t,x,y) = -VO(t,x,y) and the pressure is related to this velocity potential by p(t, x, y) = pf e(t, x, y) where pf is the equilibrium density of the fluid. For acoustic waves with small amplitude, both the potential and the pressure satisfy the undamped wave equation with uniform speed of sound c in the fluid [14,15]; hence Ott = c 2 A4…”