摘要:

A certain class of three dimensional disturbances is studied which exhibit a strong resonance and consequently lead to the rapid development of relatively large amplitudes. For parallel flows a nonlinear theory is developed and results in evolution equations quite different from those usually found. It is believed that the selection mechanism explored here is relevant to a variety of nonlinear wave and instability problems.

ISSN:0022-2526    

DOI:10.1002/sapm1981643185

年代:1981

数据来源: WILEY

摘要:

The containment capability of an impounding dike is examined for a dynamic spill in which a large volume of liquid is discharged from the rupture of a storage tank. In this situation, dikes as presently constructed and positioned would allow substantial overflow. Designs are advanced for more efficient safety dams of conventional scale and cost.

ISSN:0022-2526    

DOI:10.1002/sapm1981643211

年代:1981

数据来源: WILEY

摘要:

A direct perturbation method is developed to investigate the evolution of solitary waves in the presence of small perturbations. A uniformly valid first order solution is constructed. The method is applied to several nonlinear evolution equations which support solitons or solitary waves. Finally, the method is compared with other approaches in the literature.

ISSN:0022-2526    

DOI:10.1002/sapm1981643225

年代:1981

数据来源: WILEY

摘要:

The propagation of an internal wave train in a stratified shear flow is investigated for a Boussinesq fluid in a horizontal channel. Linear effects are primarily reflected in the dispersion relation for the various modes. The phenomenon of Eckart resonance occurs for more realistic stratification profiles. The evolution of nonlinear internal wave packets is studied through a systematic perturbation analysis. A nonlinear Schrodinger equation for the envelope of the internal wave train is derived. Depending on the relative sign of the dispersive and nonlinear terms, a wave train may disperse or form an envelope soliton. The analysis demonstrates the existence of two types of critical layers: one the ordinary critical point whereū=c, while the other occurs whereū=cg. In order to calculate the coefficients of the nonlinear Schrodinger equation a numerical code has been developed which computes the second‐harmonic and induced mean motions. The existence of these envelope solitons and their dependence on environmental conditions are discus

ISSN:0022-2526    

DOI:10.1002/sapm1981643247

年代:1981

数据来源: WILEY

摘要:

In this paper we consider the general two‐dimensional recursiong(n+ 1,r+ 1) =g(n+ 1,r) +bg(n,r) +g(n,r+ 1) with boundary conditionsg(n, 0) =g(0,r) = 1 We develop various exact and asymptotic formulas for theg(n,r

ISSN:0022-2526    

DOI:10.1002/sapm1981643271

年代:1981

数据来源: WILEY